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Theorem List for Metamath Proof Explorer - 29301-29400   *Has distinct variable group(s)
TypeLabelDescription
Statement
 
Theoremltrneq3 29301 Two translations agree at any atom not under the fiducial co-atom  W iff they are equal. (Contributed by NM, 25-Jul-2013.)
 |-  .<_  =  ( le `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  (
 LHyp `  K )   &    |-  T  =  ( ( LTrn `  K ) `  W )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( F  e.  T  /\  G  e.  T ) 
 /\  ( P  e.  A  /\  -.  P  .<_  W ) )  ->  (
 ( F `  P )  =  ( G `  P )  <->  F  =  G ) )
 
Theoremcdleme00a 29302 Part of proof of Lemma E in [Crawley] p. 113. (Contributed by NM, 14-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   =>    |-  (
 ( K  e.  HL  /\  ( P  e.  A  /\  Q  e.  A  /\  R  e.  A )  /\  -.  R  .<_  ( P 
 .\/  Q ) )  ->  R  =/=  P )
 
Theoremcdleme0aa 29303 Part of proof of Lemma E in [Crawley] p. 113. (Contributed by NM, 14-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  B  =  ( Base `  K )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  P  e.  A  /\  Q  e.  A ) 
 ->  U  e.  B )
 
Theoremcdleme0a 29304 Part of proof of Lemma E in [Crawley] p. 113. (Contributed by NM, 12-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W )  /\  ( Q  e.  A  /\  P  =/=  Q ) )  ->  U  e.  A )
 
Theoremcdleme0b 29305 Part of proof of Lemma E in [Crawley] p. 113. (Contributed by NM, 13-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W )  /\  Q  e.  A )  ->  U  =/=  P )
 
Theoremcdleme0c 29306 Part of proof of Lemma E in [Crawley] p. 113. (Contributed by NM, 12-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  Q  e.  A )  /\  ( R  e.  A  /\  -.  R  .<_  W ) )  ->  U  =/=  R )
 
Theoremcdleme0cp 29307 Part of proof of Lemma E in [Crawley] p. 113. TODO: Reformat as in cdlemg3a 29690- swap consequent equality; make antecedent use df-3an 941. (Contributed by NM, 13-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( ( P  e.  A  /\  -.  P  .<_  W )  /\  Q  e.  A )
 )  ->  ( P  .\/  U )  =  ( P  .\/  Q )
 )
 
Theoremcdleme0cq 29308 Part of proof of Lemma E in [Crawley] p. 113. (Contributed by NM, 25-Apr-2013.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  ( Q  e.  A  /\  -.  Q  .<_  W ) ) )  ->  ( Q  .\/  U )  =  ( P  .\/  Q ) )
 
Theoremcdleme0dN 29309 Part of proof of Lemma E in [Crawley] p. 113. (Contributed by NM, 13-Jun-2012.) (New usage is discouraged.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  V  =  ( ( P  .\/  R )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W )  /\  ( R  e.  A  /\  P  =/=  R ) )  ->  V  e.  A )
 
Theoremcdleme0e 29310 Part of proof of Lemma E in [Crawley] p. 113. (Contributed by NM, 13-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  V  =  ( ( P  .\/  R )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( ( P  e.  A  /\  -.  P  .<_  W )  /\  Q  e.  A  /\  ( R  e.  A  /\  -.  R  .<_  W ) )  /\  ( P  =/=  Q  /\  -.  R  .<_  ( P  .\/  Q ) ) )  ->  U  =/=  V )
 
Theoremcdleme0fN 29311 Part of proof of Lemma E in [Crawley] p. 113. (Contributed by NM, 14-Jun-2012.) (New usage is discouraged.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  V  =  ( ( P  .\/  R )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W )  /\  ( Q  e.  A  /\  R  e.  A ) )  ->  V  =/=  P )
 
Theoremcdleme0gN 29312 Part of proof of Lemma E in [Crawley] p. 113. (Contributed by NM, 14-Jun-2012.) (New usage is discouraged.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  V  =  ( ( P  .\/  R )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  R  e.  A )  /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  ->  V  =/=  Q )
 
Theoremcdlemeulpq 29313 Part of proof of Lemma E in [Crawley] p. 113. (Contributed by NM, 5-Dec-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  Q  e.  A ) )  ->  U  .<_  ( P  .\/  Q )
 )
 
Theoremcdleme01N 29314 Part of proof of Lemma E in [Crawley] p. 113. (Contributed by NM, 5-Nov-2012.) (New usage is discouraged.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( ( P  e.  A  /\  -.  P  .<_  W )  /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  P  =/=  Q )  ->  ( ( U  =/=  P  /\  U  =/=  Q  /\  U  .<_  ( P  .\/  Q )
 )  /\  U  .<_  W ) )
 
Theoremcdleme02N 29315 Part of proof of Lemma E in [Crawley] p. 113. (Contributed by NM, 9-Nov-2012.) (New usage is discouraged.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( ( P  e.  A  /\  -.  P  .<_  W )  /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  P  =/=  Q )  ->  ( ( P  .\/  U )  =  ( Q  .\/  U )  /\  U  .<_  W ) )
 
Theoremcdleme0ex1N 29316* Part of proof of Lemma E in [Crawley] p. 113. (Contributed by NM, 9-Nov-2012.) (New usage is discouraged.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( ( P  e.  A  /\  -.  P  .<_  W )  /\  Q  e.  A )  /\  P  =/=  Q ) 
 ->  E. u  e.  A  ( u  .<_  ( P 
 .\/  Q )  /\  u  .<_  W ) )
 
Theoremcdleme0ex2N 29317* Part of proof of Lemma E in [Crawley] p. 113. Note that  ( P  .\/  u )  =  ( Q  .\/  u ) is a shorter way to express  u  =/=  P  /\  u  =/=  Q  /\  u  .<_  ( P 
.\/  Q ). (Contributed by NM, 9-Nov-2012.) (New usage is discouraged.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( ( P  e.  A  /\  -.  P  .<_  W )  /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  P  =/=  Q )  ->  E. u  e.  A  ( ( P 
 .\/  u )  =  ( Q  .\/  u )  /\  u  .<_  W ) )
 
Theoremcdleme0moN 29318* Part of proof of Lemma E in [Crawley] p. 113. (Contributed by NM, 9-Nov-2012.) (New usage is discouraged.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( ( P  e.  A  /\  -.  P  .<_  W )  /\  ( Q  e.  A  /\  -.  Q  .<_  W ) 
 /\  ( R  e.  A  /\  -.  R  .<_  W ) )  /\  ( P  =/=  Q  /\  R  .<_  ( P  .\/  Q )  /\  E* r ( r  e.  A  /\  ( P  .\/  r )  =  ( Q  .\/  r ) ) ) )  ->  ( R  =  P  \/  R  =  Q ) )
 
Theoremcdleme1b 29319 Part of proof of Lemma E in [Crawley] p. 113. Utility lemma showing  F is a lattice element.  F represents their f(r). (Contributed by NM, 6-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( R  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  R )  ./\  W )
 ) )   &    |-  B  =  (
 Base `  K )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  Q  e.  A  /\  R  e.  A )
 )  ->  F  e.  B )
 
Theoremcdleme1 29320 Part of proof of Lemma E in [Crawley] p. 113.  F represents their f(r). Here we show r  \/ f(r) = r  \/ u (7th through 5th lines from bottom on p. 113). (Contributed by NM, 4-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( R  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  R )  ./\  W )
 ) )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  Q  e.  A  /\  ( R  e.  A  /\  -.  R  .<_  W ) ) )  ->  ( R  .\/  F )  =  ( R  .\/  U ) )
 
Theoremcdleme2 29321 Part of proof of Lemma E in [Crawley] p. 113. .  F represents f(r).  W is the fiducial co-atom (hyperplane) w. Here we show that (r  \/ f(r))  /\ w = u in their notation (4th line from bottom on p. 113). (Contributed by NM, 5-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( R  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  R )  ./\  W )
 ) )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  Q  e.  A  /\  ( R  e.  A  /\  -.  R  .<_  W ) ) )  ->  (
 ( R  .\/  F )  ./\  W )  =  U )
 
Theoremcdleme3b 29322 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme3fa 29329 and cdleme3 29330. (Contributed by NM, 6-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( R  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  R )  ./\  W )
 ) )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  (
 ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  P  =/=  Q )  /\  ( R  e.  A  /\  -.  R  .<_  W ) ) )  ->  F  =/=  R )
 
Theoremcdleme3c 29323 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme3fa 29329 and cdleme3 29330. (Contributed by NM, 6-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( R  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  R )  ./\  W )
 ) )   &    |-  .0.  =  ( 0. `  K )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  (
 ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  P  =/=  Q )  /\  ( R  e.  A  /\  -.  R  .<_  W ) ) )  ->  F  =/=  .0.  )
 
Theoremcdleme3d 29324 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme3fa 29329 and cdleme3 29330. (Contributed by NM, 6-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( R  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  R )  ./\  W )
 ) )   &    |-  V  =  ( ( P  .\/  R )  ./\  W )   =>    |-  F  =  ( ( R  .\/  U )  ./\  ( Q  .\/  V ) )
 
Theoremcdleme3e 29325 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme3fa 29329 and cdleme3 29330. (Contributed by NM, 6-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( R  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  R )  ./\  W )
 ) )   &    |-  V  =  ( ( P  .\/  R )  ./\  W )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( ( P  e.  A  /\  -.  P  .<_  W )  /\  Q  e.  A  /\  ( R  e.  A  /\  -.  R  .<_  ( P  .\/  Q )
 ) ) )  ->  V  e.  A )
 
Theoremcdleme3fN 29326 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme3fa 29329 and cdleme3 29330. TODO: Delete - duplicates cdleme0e 29310. (Contributed by NM, 6-Jun-2012.) (New usage is discouraged.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( R  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  R )  ./\  W )
 ) )   &    |-  V  =  ( ( P  .\/  R )  ./\  W )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( ( P  e.  A  /\  -.  P  .<_  W )  /\  Q  e.  A  /\  ( R  e.  A  /\  -.  R  .<_  W ) )  /\  ( P  =/=  Q  /\  -.  R  .<_  ( P  .\/  Q ) ) )  ->  U  =/=  V )
 
Theoremcdleme3g 29327 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme3fa 29329 and cdleme3 29330. (Contributed by NM, 7-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( R  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  R )  ./\  W )
 ) )   &    |-  V  =  ( ( P  .\/  R )  ./\  W )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( ( P  e.  A  /\  -.  P  .<_  W )  /\  ( Q  e.  A  /\  -.  Q  .<_  W )  /\  ( R  e.  A  /\  -.  R  .<_  W ) )  /\  ( P  =/=  Q  /\  -.  R  .<_  ( P  .\/  Q ) ) )  ->  F  =/=  U )
 
Theoremcdleme3h 29328 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme3fa 29329 and cdleme3 29330. (Contributed by NM, 6-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( R  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  R )  ./\  W )
 ) )   &    |-  V  =  ( ( P  .\/  R )  ./\  W )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( ( P  e.  A  /\  -.  P  .<_  W )  /\  ( Q  e.  A  /\  -.  Q  .<_  W )  /\  ( R  e.  A  /\  -.  R  .<_  W ) )  /\  ( P  =/=  Q  /\  -.  R  .<_  ( P  .\/  Q ) ) )  ->  F  e.  A )
 
Theoremcdleme3fa 29329 Part of proof of Lemma E in [Crawley] p. 113. See cdleme3 29330. (Contributed by NM, 6-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( R  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  R )  ./\  W )
 ) )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  (
 ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W )  /\  ( R  e.  A  /\  -.  R  .<_  W ) ) 
 /\  ( P  =/=  Q 
 /\  -.  R  .<_  ( P  .\/  Q )
 ) )  ->  F  e.  A )
 
Theoremcdleme3 29330 Part of proof of Lemma E in [Crawley] p. 113.  F represents f(r).  W is the fiducial co-atom (hyperplane) w. Here and in cdleme3fa 29329 above, we show that f(r)  e. W (4th line from bottom on p. 113), meaning it is an atom and not under w, which in our notation is expressed as  F  e.  A  /\  -.  F  .<_  W. Their proof provides no details of our lemmas cdleme3b 29322 through cdleme3 29330, so there may be a simpler proof that we have overlooked. (Contributed by NM, 7-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( R  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  R )  ./\  W )
 ) )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  (
 ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W )  /\  ( R  e.  A  /\  -.  R  .<_  W ) ) 
 /\  ( P  =/=  Q 
 /\  -.  R  .<_  ( P  .\/  Q )
 ) )  ->  -.  F  .<_  W )
 
Theoremcdleme4 29331 Part of proof of Lemma E in [Crawley] p. 113.  F and  G represent f(s) and fs(r). Here show p  \/ q = r  \/ u at the top of p. 114. (Contributed by NM, 7-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  Q  e.  A  /\  ( R  e.  A  /\  -.  R  .<_  W ) )  /\  R  .<_  ( P  .\/  Q )
 )  ->  ( P  .\/  Q )  =  ( R  .\/  U )
 )
 
Theoremcdleme4a 29332 Part of proof of Lemma E in [Crawley] p. 114 top.  G represents fs(r). Auxiliary lemma derived from cdleme5 29333. We show fs(r)  <_ p  \/ q. (Contributed by NM, 10-Nov-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  ( ( R  .\/  S )  ./\  W )
 ) )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  Q  e.  A  /\  R  e.  A )  /\  S  e.  A ) 
 ->  G  .<_  ( P  .\/  Q ) )
 
Theoremcdleme5 29333 Part of proof of Lemma E in [Crawley] p. 113.  G represents fs(r). We show r  \/ fs(r)) = p  \/ q at the top of p. 114. (Contributed by NM, 7-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  ( ( R  .\/  S )  ./\  W )
 ) )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  Q  e.  A  /\  ( R  e.  A  /\  -.  R  .<_  W ) )  /\  ( ( S  e.  A  /\  -.  S  .<_  W )  /\  R  .<_  ( P  .\/  Q ) ) )  ->  ( R  .\/  G )  =  ( P  .\/  Q ) )
 
Theoremcdleme6 29334 Part of proof of Lemma E in [Crawley] p. 113. This expresses (r  \/ fs(r))  /\ w = u at the top of p. 114. (Contributed by NM, 7-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  ( ( R  .\/  S )  ./\  W )
 ) )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  Q  e.  A  /\  ( R  e.  A  /\  -.  R  .<_  W ) )  /\  ( ( S  e.  A  /\  -.  S  .<_  W )  /\  R  .<_  ( P  .\/  Q ) ) )  ->  ( ( R  .\/  G )  ./\  W )  =  U )
 
Theoremcdleme7aa 29335 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme7ga 29341 and cdleme7 29342. (Contributed by NM, 7-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  ( ( R  .\/  S )  ./\  W )
 ) )   =>    |-  ( ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  Q  e.  A )  /\  ( ( R  e.  A  /\  -.  R  .<_  W )  /\  ( S  e.  A  /\  -.  S  .<_  W ) )  /\  ( P  =/=  Q  /\  R  .<_  ( P  .\/  Q )  /\  -.  S  .<_  ( P  .\/  Q )
 ) )  ->  -.  R  .<_  ( U  .\/  S ) )
 
Theoremcdleme7a 29336 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme7ga 29341 and cdleme7 29342. (Contributed by NM, 7-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  ( ( R  .\/  S )  ./\  W )
 ) )   &    |-  V  =  ( ( R  .\/  S )  ./\  W )   =>    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  V ) )
 
Theoremcdleme7b 29337 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme7ga 29341 and cdleme7 29342. (Contributed by NM, 7-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  ( ( R  .\/  S )  ./\  W )
 ) )   &    |-  V  =  ( ( R  .\/  S )  ./\  W )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( R  e.  A  /\  -.  R  .<_  W ) 
 /\  ( S  e.  A  /\  -.  S  .<_  ( P  .\/  Q )  /\  R  .<_  ( P  .\/  Q ) ) )  ->  V  e.  A )
 
Theoremcdleme7c 29338 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme7ga 29341 and cdleme7 29342. (Contributed by NM, 7-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  ( ( R  .\/  S )  ./\  W )
 ) )   &    |-  V  =  ( ( R  .\/  S )  ./\  W )   =>    |-  ( ( ( ( K  e.  HL  /\  W  e.  H ) 
 /\  ( P  e.  A  /\  -.  P  .<_  W )  /\  Q  e.  A )  /\  ( ( R  e.  A  /\  -.  R  .<_  W )  /\  ( S  e.  A  /\  -.  S  .<_  W ) )  /\  ( P  =/=  Q  /\  R  .<_  ( P  .\/  Q )  /\  -.  S  .<_  ( P  .\/  Q )
 ) )  ->  U  =/=  V )
 
Theoremcdleme7d 29339 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme7ga 29341 and cdleme7 29342. (Contributed by NM, 8-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  ( ( R  .\/  S )  ./\  W )
 ) )   &    |-  V  =  ( ( R  .\/  S )  ./\  W )   =>    |-  ( ( ( ( K  e.  HL  /\  W  e.  H ) 
 /\  ( P  e.  A  /\  -.  P  .<_  W )  /\  ( Q  e.  A  /\  -.  Q  .<_  W ) ) 
 /\  ( ( R  e.  A  /\  -.  R  .<_  W )  /\  ( S  e.  A  /\  -.  S  .<_  W ) )  /\  ( P  =/=  Q  /\  R  .<_  ( P  .\/  Q )  /\  -.  S  .<_  ( P  .\/  Q )
 ) )  ->  G  =/=  U )
 
Theoremcdleme7e 29340 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme7ga 29341 and cdleme7 29342. (Contributed by NM, 8-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  ( ( R  .\/  S )  ./\  W )
 ) )   &    |-  V  =  ( ( R  .\/  S )  ./\  W )   =>    |-  ( ( ( ( K  e.  HL  /\  W  e.  H ) 
 /\  ( P  e.  A  /\  -.  P  .<_  W )  /\  ( Q  e.  A  /\  -.  Q  .<_  W ) ) 
 /\  ( ( R  e.  A  /\  -.  R  .<_  W )  /\  ( S  e.  A  /\  -.  S  .<_  W ) )  /\  ( P  =/=  Q  /\  R  .<_  ( P  .\/  Q )  /\  -.  S  .<_  ( P  .\/  Q )
 ) )  ->  G  =/=  ( 0. `  K ) )
 
Theoremcdleme7ga 29341 Part of proof of Lemma E in [Crawley] p. 113. See cdleme7 29342. (Contributed by NM, 8-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  ( ( R  .\/  S )  ./\  W )
 ) )   =>    |-  ( ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  (
 ( R  e.  A  /\  -.  R  .<_  W ) 
 /\  ( S  e.  A  /\  -.  S  .<_  W ) )  /\  ( P  =/=  Q  /\  R  .<_  ( P  .\/  Q )  /\  -.  S  .<_  ( P  .\/  Q )
 ) )  ->  G  e.  A )
 
Theoremcdleme7 29342 Part of proof of Lemma E in [Crawley] p. 113.  G and  F represent fs(r) and f(s) respectively.  W is the fiducial co-atom (hyperplane) that they call w. Here and in cdleme7ga 29341 above, we show that fs(r)  e. W (top of p. 114), meaning it is an atom and not under w, which in our notation is expressed as  G  e.  A  /\  -.  G  .<_  W. (Note that we do not have a symbol for their W.) Their proof provides no details of our cdleme7aa 29335 through cdleme7 29342, so there may be a simpler proof that we have overlooked. (Contributed by NM, 9-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  ( ( R  .\/  S )  ./\  W )
 ) )   =>    |-  ( ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  (
 ( R  e.  A  /\  -.  R  .<_  W ) 
 /\  ( S  e.  A  /\  -.  S  .<_  W ) )  /\  ( P  =/=  Q  /\  R  .<_  ( P  .\/  Q )  /\  -.  S  .<_  ( P  .\/  Q )
 ) )  ->  -.  G  .<_  W )
 
Theoremcdleme8 29343 Part of proof of Lemma E in [Crawley] p. 113, 2nd paragraph on p. 114.  C represents s1. In their notation, we prove p  \/ s1 = p  \/ s. (Contributed by NM, 9-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  C  =  ( ( P  .\/  S )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W )  /\  S  e.  A )  ->  ( P 
 .\/  C )  =  ( P  .\/  S )
 )
 
Theoremcdleme9a 29344 Part of proof of Lemma E in [Crawley] p. 113.  C represents s1, which we prove is an atom. (Contributed by NM, 10-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  C  =  ( ( P  .\/  S )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W )  /\  ( S  e.  A  /\  P  =/=  S ) )  ->  C  e.  A )
 
Theoremcdleme9b 29345 Utility lemma for Lemma E in [Crawley] p. 113. (Contributed by NM, 9-Oct-2012.)
 |-  B  =  ( Base `  K )   &    |-  .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  C  =  ( ( P  .\/  S )  ./\  W )   =>    |-  (
 ( K  e.  HL  /\  ( P  e.  A  /\  S  e.  A  /\  W  e.  H )
 )  ->  C  e.  B )
 
Theoremcdleme9 29346 Part of proof of Lemma E in [Crawley] p. 113, 2nd paragraph on p. 114.  C and  F represent s1 and f(s) respectively. In their notation, we prove f(s)  \/ s1 = q  \/ s1. (Contributed by NM, 10-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  C  =  ( ( P  .\/  S )  ./\  W )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( ( P  e.  A  /\  -.  P  .<_  W )  /\  Q  e.  A  /\  ( S  e.  A  /\  -.  S  .<_  W ) )  /\  -.  S  .<_  ( P  .\/  Q ) )  ->  ( F  .\/  C )  =  ( Q  .\/  C ) )
 
Theoremcdleme10 29347 Part of proof of Lemma E in [Crawley] p. 113, 2nd paragraph on p. 114.  D represents s2. In their notation, we prove s  \/ s2 = s  \/ r. (Contributed by NM, 9-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  D  =  ( ( R  .\/  S )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  R  e.  A  /\  ( S  e.  A  /\  -.  S  .<_  W ) )  ->  ( S  .\/  D )  =  ( S  .\/  R )
 )
 
Theoremcdleme8tN 29348 Part of proof of Lemma E in [Crawley] p. 113, 2nd paragraph on p. 114.  X represents t1. In their notation, we prove p  \/ t1 = p  \/ t. (Contributed by NM, 8-Oct-2012.) (New usage is discouraged.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  X  =  ( ( P  .\/  T )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W )  /\  T  e.  A )  ->  ( P 
 .\/  X )  =  ( P  .\/  T )
 )
 
Theoremcdleme9taN 29349 Part of proof of Lemma E in [Crawley] p. 113.  X represents t1, which we prove is an atom. (Contributed by NM, 8-Oct-2012.) (New usage is discouraged.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  X  =  ( ( P  .\/  T )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W )  /\  ( T  e.  A  /\  P  =/=  T ) )  ->  X  e.  A )
 
Theoremcdleme9tN 29350 Part of proof of Lemma E in [Crawley] p. 113, 2nd paragraph on p. 114.  X and  F represent t1 and f(t) respectively. In their notation, we prove f(t)  \/ t1 = q  \/ t1. (Contributed by NM, 8-Oct-2012.) (New usage is discouraged.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   &    |-  X  =  ( ( P  .\/  T )  ./\  W )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( ( P  e.  A  /\  -.  P  .<_  W )  /\  Q  e.  A  /\  ( T  e.  A  /\  -.  T  .<_  W ) )  /\  -.  T  .<_  ( P  .\/  Q ) )  ->  ( F  .\/  X )  =  ( Q  .\/  X ) )
 
Theoremcdleme10tN 29351 Part of proof of Lemma E in [Crawley] p. 113, 2nd paragraph on p. 114.  Y represents t2. In their notation, we prove t  \/ t2 = t  \/ r. (Contributed by NM, 8-Oct-2012.) (New usage is discouraged.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  Y  =  ( ( R  .\/  T )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  R  e.  A  /\  ( T  e.  A  /\  -.  T  .<_  W ) )  ->  ( T  .\/  Y )  =  ( T  .\/  R )
 )
 
Theoremcdleme16aN 29352 Part of proof of Lemma E in [Crawley] p. 113, 3rd paragraph on p. 114, showing, in their notation, s  \/ u  =/= t  \/ u. (Contributed by NM, 9-Oct-2012.) (New usage is discouraged.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   =>    |-  (
 ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W ) ) 
 /\  ( Q  e.  A  /\  S  e.  A  /\  T  e.  A ) 
 /\  ( P  =/=  Q 
 /\  S  =/=  T  /\  -.  U  .<_  ( S 
 .\/  T ) ) ) 
 ->  ( S  .\/  U )  =/=  ( T  .\/  U ) )
 
Theoremcdleme11a 29353 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme11 29363. (Contributed by NM, 12-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( ( P  e.  A  /\  -.  P  .<_  W )  /\  ( Q  e.  A  /\  P  =/=  Q ) )  /\  ( ( S  e.  A  /\  -.  S  .<_  W )  /\  ( T  e.  A  /\  U  .<_  ( S  .\/  T ) ) ) ) 
 ->  ( S  .\/  U )  =  ( S  .\/  T ) )
 
Theoremcdleme11c 29354 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme11 29363. (Contributed by NM, 13-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   =>    |-  (
 ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W )  /\  Q  e.  A )  /\  ( ( S  e.  A  /\  -.  S  .<_  W )  /\  T  e.  A  /\  P  =/=  Q )  /\  ( -.  S  .<_  ( P  .\/  Q )  /\  U  .<_  ( S 
 .\/  T ) ) ) 
 ->  -.  P  .<_  ( S 
 .\/  T ) )
 
Theoremcdleme11dN 29355 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme11 29363. (Contributed by NM, 13-Jun-2012.) (New usage is discouraged.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   =>    |-  (
 ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W )  /\  Q  e.  A )  /\  ( ( S  e.  A  /\  -.  S  .<_  W )  /\  T  e.  A  /\  P  =/=  Q )  /\  ( S  =/=  T 
 /\  -.  S  .<_  ( P  .\/  Q )  /\  U  .<_  ( S  .\/  T ) ) )  ->  ( P  .\/  S )  =/=  ( P  .\/  T ) )
 
Theoremcdleme11e 29356 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme11 29363. (Contributed by NM, 13-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  C  =  ( ( P  .\/  S )  ./\  W )   &    |-  D  =  ( ( P  .\/  T )  ./\  W )   =>    |-  (
 ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W )  /\  Q  e.  A )  /\  ( ( S  e.  A  /\  -.  S  .<_  W )  /\  T  e.  A  /\  P  =/=  Q )  /\  ( S  =/=  T 
 /\  -.  S  .<_  ( P  .\/  Q )  /\  U  .<_  ( S  .\/  T ) ) )  ->  C  =/=  D )
 
Theoremcdleme11fN 29357 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme11 29363. (Contributed by NM, 14-Jun-2012.) (New usage is discouraged.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  C  =  ( ( P  .\/  S )  ./\  W )   &    |-  D  =  ( ( P  .\/  T )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  (
 ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W )  /\  ( S  e.  A  /\  -.  S  .<_  W ) ) 
 /\  ( P  =/=  Q 
 /\  -.  S  .<_  ( P  .\/  Q )
 ) )  ->  F  =/=  C )
 
Theoremcdleme11g 29358 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme11 29363. (Contributed by NM, 14-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  C  =  ( ( P  .\/  S )  ./\  W )   &    |-  D  =  ( ( P  .\/  T )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  ( Q  e.  A  /\  -.  Q  .<_  W ) 
 /\  S  e.  A )  /\  P  =/=  Q )  ->  ( Q  .\/  F )  =  ( Q 
 .\/  C ) )
 
Theoremcdleme11h 29359 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme11 29363. (Contributed by NM, 14-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  C  =  ( ( P  .\/  S )  ./\  W )   &    |-  D  =  ( ( P  .\/  T )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  (
 ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W )  /\  S  e.  A )  /\  ( P  =/=  Q  /\  -.  S  .<_  ( P  .\/  Q ) ) )  ->  F  =/=  Q )
 
Theoremcdleme11j 29360 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme11 29363. (Contributed by NM, 14-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  C  =  ( ( P  .\/  S )  ./\  W )   &    |-  D  =  ( ( P  .\/  T )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  (
 ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W )  /\  ( S  e.  A  /\  -.  S  .<_  W ) ) 
 /\  ( P  =/=  Q 
 /\  -.  S  .<_  ( P  .\/  Q )
 ) )  ->  C  .<_  ( Q  .\/  F ) )
 
Theoremcdleme11k 29361 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme11 29363. (Contributed by NM, 15-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  C  =  ( ( P  .\/  S )  ./\  W )   &    |-  D  =  ( ( P  .\/  T )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  (
 ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W )  /\  ( S  e.  A  /\  -.  S  .<_  W ) ) 
 /\  ( P  =/=  Q 
 /\  -.  S  .<_  ( P  .\/  Q )
 ) )  ->  C  =  ( ( Q  .\/  F )  ./\  W )
 )
 
Theoremcdleme11l 29362 Part of proof of Lemma E in [Crawley] p. 113. Lemma leading to cdleme11 29363. (Contributed by NM, 15-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   =>    |-  ( ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  (
 ( S  e.  A  /\  -.  S  .<_  W ) 
 /\  ( T  e.  A  /\  -.  T  .<_  W )  /\  ( P  =/=  Q  /\  S  =/=  T ) )  /\  ( -.  S  .<_  ( P 
 .\/  Q )  /\  -.  T  .<_  ( P  .\/  Q )  /\  U  .<_  ( S  .\/  T )
 ) )  ->  F  =/=  G )
 
Theoremcdleme11 29363 Part of proof of Lemma E in [Crawley] p. 113, 1st sentence of 3rd paragraph on p. 114.  F and  G represent f(s) and f(t) respectively. Their proof provides no details of our cdleme11a 29353 through cdleme11 29363, so there may be a simpler proof that we have overlooked. (Contributed by NM, 15-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   =>    |-  ( ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  (
 ( S  e.  A  /\  -.  S  .<_  W ) 
 /\  ( T  e.  A  /\  -.  T  .<_  W )  /\  ( P  =/=  Q  /\  S  =/=  T ) )  /\  ( -.  S  .<_  ( P 
 .\/  Q )  /\  -.  T  .<_  ( P  .\/  Q )  /\  U  .<_  ( S  .\/  T )
 ) )  ->  ( F  .\/  G )  =  ( S  .\/  T ) )
 
Theoremcdleme12 29364 Part of proof of Lemma E in [Crawley] p. 113, 3rd paragraph on p. 114, first part of 3rd sentence. 
F and  G represent f(s) and f(t) respectively. (Contributed by NM, 16-Jun-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  (
 ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  Q  e.  A  /\  P  =/=  Q ) 
 /\  ( ( S  e.  A  /\  -.  S  .<_  W )  /\  ( T  e.  A  /\  -.  T  .<_  W ) 
 /\  ( S  =/=  T 
 /\  -.  U  .<_  ( S  .\/  T )
 ) ) )  ->  ( ( S  .\/  F )  ./\  ( T  .\/  G ) )  =  U )
 
Theoremcdleme13 29365 Part of proof of Lemma E in [Crawley] p. 113, 3rd paragraph on p. 114, "<s,t,p> and <f(s),f(t),q> are centrally perspective."  F and  G represent f(s) and f(t) respectively. (Contributed by NM, 7-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  (
 ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  Q  e.  A  /\  P  =/=  Q ) 
 /\  ( ( S  e.  A  /\  -.  S  .<_  W )  /\  ( T  e.  A  /\  -.  T  .<_  W ) 
 /\  ( S  =/=  T 
 /\  -.  U  .<_  ( S  .\/  T )
 ) ) )  ->  ( ( S  .\/  F )  ./\  ( T  .\/  G ) )  .<_  ( P  .\/  Q )
 )
 
Theoremcdleme14 29366 Part of proof of Lemma E in [Crawley] p. 113, 3rd paragraph on p. 114, "<s,t,p> and <f(s),f(t),q> ... are axially perspective." We apply dalaw 28979 to cdleme13 29365. 
F and  G represent f(s) and f(t) respectively. (Contributed by NM, 8-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   =>    |-  ( ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  (
 ( S  e.  A  /\  -.  S  .<_  W ) 
 /\  ( T  e.  A  /\  -.  T  .<_  W )  /\  ( P  =/=  Q  /\  S  =/=  T ) )  /\  ( -.  S  .<_  ( P 
 .\/  Q )  /\  -.  T  .<_  ( P  .\/  Q )  /\  -.  U  .<_  ( S  .\/  T ) ) )  ->  ( ( S  .\/  T )  ./\  ( F  .\/  G ) )  .<_  ( ( ( T  .\/  P )  ./\  ( G  .\/  Q ) )  .\/  ( ( P  .\/  S )  ./\  ( Q  .\/  F ) ) ) )
 
Theoremcdleme15a 29367 Part of proof of Lemma E in [Crawley] p. 113, 3rd paragraph on p. 114, showing, in their notation, ((s  \/ p)  /\ (f(s)  \/ q))  \/ ((t  \/ p)  /\ (f(t)  \/ q))=((p  \/ s1)  /\ (q  \/ s1))  \/ ((p  \/ t1)  /\ (q 
\/ t1)). We represent f(s), f(t), s1, and t1 with  F,  G,  C, and  X respectively. The order of our operations is slightly different. (Contributed by NM, 9-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   &    |-  C  =  ( ( P  .\/  S )  ./\  W )   &    |-  X  =  ( ( P  .\/  T )  ./\  W )   =>    |-  (
 ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W )  /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  ( ( S  e.  A  /\  -.  S  .<_  W )  /\  ( T  e.  A  /\  -.  T  .<_  W ) 
 /\  ( P  =/=  Q 
 /\  S  =/=  T ) )  /\  ( -.  S  .<_  ( P  .\/  Q )  /\  -.  T  .<_  ( P  .\/  Q )  /\  -.  U  .<_  ( S  .\/  T )
 ) )  ->  (
 ( ( T  .\/  P )  ./\  ( G  .\/  Q ) )  .\/  ( ( P  .\/  S )  ./\  ( Q  .\/  F ) ) )  =  ( ( ( P  .\/  X )  ./\  ( Q  .\/  X ) )  .\/  ( ( P  .\/  C )  ./\  ( Q  .\/  C ) ) ) )
 
Theoremcdleme15b 29368 Part of proof of Lemma E in [Crawley] p. 113, 3rd paragraph on p. 114, showing, in their notation, (p  \/ s1)  /\ (q  \/ s1)=s1. We represent s1 with  C. (Contributed by NM, 10-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   &    |-  C  =  ( ( P  .\/  S )  ./\  W )   &    |-  X  =  ( ( P  .\/  T )  ./\  W )   =>    |-  (
 ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W )  /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  ( ( S  e.  A  /\  -.  S  .<_  W )  /\  ( T  e.  A  /\  -.  T  .<_  W ) 
 /\  ( P  =/=  Q 
 /\  S  =/=  T ) )  /\  ( -.  S  .<_  ( P  .\/  Q )  /\  -.  T  .<_  ( P  .\/  Q )  /\  -.  U  .<_  ( S  .\/  T )
 ) )  ->  (
 ( P  .\/  C )  ./\  ( Q  .\/  C ) )  =  C )
 
Theoremcdleme15c 29369 Part of proof of Lemma E in [Crawley] p. 113, 3rd paragraph on p. 114, showing, in their notation, ((p  \/ s1)  /\ (q  \/ s1))  \/ ((p  \/ t1)  /\ (q  \/ t1))=s1  \/ t1.  C and  X represent s1 and t1 respectively. The order of our operations is slightly different. (Contributed by NM, 10-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   &    |-  C  =  ( ( P  .\/  S )  ./\  W )   &    |-  X  =  ( ( P  .\/  T )  ./\  W )   =>    |-  (
 ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W )  /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  ( ( S  e.  A  /\  -.  S  .<_  W )  /\  ( T  e.  A  /\  -.  T  .<_  W ) 
 /\  ( P  =/=  Q 
 /\  S  =/=  T ) )  /\  ( -.  S  .<_  ( P  .\/  Q )  /\  -.  T  .<_  ( P  .\/  Q )  /\  -.  U  .<_  ( S  .\/  T )
 ) )  ->  (
 ( ( P  .\/  X )  ./\  ( Q  .\/  X ) )  .\/  ( ( P  .\/  C )  ./\  ( Q  .\/  C ) ) )  =  ( X  .\/  C ) )
 
Theoremcdleme15d 29370 Part of proof of Lemma E in [Crawley] p. 113, 3rd paragraph on p. 114, showing, in their notation, s1  \/ t1  <_ w.  C and  X represent s1 and t1 respectively. The order of our operations is slightly different. (Contributed by NM, 10-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   &    |-  C  =  ( ( P  .\/  S )  ./\  W )   &    |-  X  =  ( ( P  .\/  T )  ./\  W )   =>    |-  (
 ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W )  /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  ( ( S  e.  A  /\  -.  S  .<_  W )  /\  ( T  e.  A  /\  -.  T  .<_  W ) 
 /\  ( P  =/=  Q 
 /\  S  =/=  T ) )  /\  ( -.  S  .<_  ( P  .\/  Q )  /\  -.  T  .<_  ( P  .\/  Q )  /\  -.  U  .<_  ( S  .\/  T )
 ) )  ->  ( X  .\/  C )  .<_  W )
 
Theoremcdleme15 29371 Part of proof of Lemma E in [Crawley] p. 113, 3rd paragraph on p. 114, showing, in their notation, (s  \/ t)  /\ (f(s)  \/ f(t))  <_ w. We use  F,  G for f(s), f(t) respectively. (Contributed by NM, 10-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   =>    |-  ( ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  (
 ( S  e.  A  /\  -.  S  .<_  W ) 
 /\  ( T  e.  A  /\  -.  T  .<_  W )  /\  ( P  =/=  Q  /\  S  =/=  T ) )  /\  ( -.  S  .<_  ( P 
 .\/  Q )  /\  -.  T  .<_  ( P  .\/  Q )  /\  -.  U  .<_  ( S  .\/  T ) ) )  ->  ( ( S  .\/  T )  ./\  ( F  .\/  G ) )  .<_  W )
 
Theoremcdleme16b 29372 Part of proof of Lemma E in [Crawley] p. 113, 3rd paragraph on p. 114, first part of 3rd sentence. 
F and  G represent f(s) and f(t) respectively. It is unclear how this follows from s  \/ u  =/= t  \/ u, as the authors state, and we used a different proof. (Note: the antecedent  -.  T  .<_  ( P 
.\/  Q ) is not used.) (Contributed by NM, 11-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   =>    |-  ( ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  (
 ( S  e.  A  /\  -.  S  .<_  W ) 
 /\  ( T  e.  A  /\  -.  T  .<_  W )  /\  ( P  =/=  Q  /\  S  =/=  T ) )  /\  ( -.  S  .<_  ( P 
 .\/  Q )  /\  -.  T  .<_  ( P  .\/  Q )  /\  -.  U  .<_  ( S  .\/  T ) ) )  ->  F  =/=  G )
 
Theoremcdleme16c 29373 Part of proof of Lemma E in [Crawley] p. 113, 3rd paragraph on p. 114, 2nd part of 3rd sentence.  F and  G represent f(s) and f(t) respectively. We show, in their notation, s  \/ t 
\/ f(s)  \/ f(t)=s  \/ t  \/ u. (Contributed by NM, 11-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   =>    |-  ( ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  (
 ( S  e.  A  /\  -.  S  .<_  W ) 
 /\  ( T  e.  A  /\  -.  T  .<_  W )  /\  ( P  =/=  Q  /\  S  =/=  T ) )  /\  ( -.  S  .<_  ( P 
 .\/  Q )  /\  -.  T  .<_  ( P  .\/  Q )  /\  -.  U  .<_  ( S  .\/  T ) ) )  ->  ( ( S  .\/  T )  .\/  ( F  .\/  G ) )  =  ( ( S  .\/  T )  .\/  U )
 )
 
Theoremcdleme16d 29374 Part of proof of Lemma E in [Crawley] p. 113, 3rd paragraph on p. 114, 3rd part of 3rd sentence.  F and  G represent f(s) and f(t) respectively. We show, in their notation, (s  \/ t)  /\ (f(s)  \/ f(t)) is an atom. (Contributed by NM, 11-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   =>    |-  ( ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  (
 ( S  e.  A  /\  -.  S  .<_  W ) 
 /\  ( T  e.  A  /\  -.  T  .<_  W )  /\  ( P  =/=  Q  /\  S  =/=  T ) )  /\  ( -.  S  .<_  ( P 
 .\/  Q )  /\  -.  T  .<_  ( P  .\/  Q )  /\  -.  U  .<_  ( S  .\/  T ) ) )  ->  ( ( S  .\/  T )  ./\  ( F  .\/  G ) )  e.  A )
 
Theoremcdleme16e 29375 Part of proof of Lemma E in [Crawley] p. 113, 3rd paragraph on p. 114, 3rd part of 3rd sentence.  F and  G represent f(s) and f(t) respectively. We show, in their notation, (s  \/ t)  /\ (f(s)  \/ f(t))=(s  \/ t)  /\ w. (Contributed by NM, 11-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   =>    |-  ( ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  (
 ( S  e.  A  /\  -.  S  .<_  W ) 
 /\  ( T  e.  A  /\  -.  T  .<_  W )  /\  ( P  =/=  Q  /\  S  =/=  T ) )  /\  ( -.  S  .<_  ( P 
 .\/  Q )  /\  -.  T  .<_  ( P  .\/  Q )  /\  -.  U  .<_  ( S  .\/  T ) ) )  ->  ( ( S  .\/  T )  ./\  ( F  .\/  G ) )  =  ( ( S  .\/  T )  ./\  W )
 )
 
Theoremcdleme16f 29376 Part of proof of Lemma E in [Crawley] p. 113, 3rd paragraph on p. 114, 3rd part of 3rd sentence.  F and  G represent f(s) and f(t) respectively. We show, in their notation, (s  \/ t)  /\ (f(s)  \/ f(t))=(f(s)  \/ f(t))  /\ w. (Contributed by NM, 11-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   =>    |-  ( ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  (
 ( S  e.  A  /\  -.  S  .<_  W ) 
 /\  ( T  e.  A  /\  -.  T  .<_  W )  /\  ( P  =/=  Q  /\  S  =/=  T ) )  /\  ( -.  S  .<_  ( P 
 .\/  Q )  /\  -.  T  .<_  ( P  .\/  Q )  /\  -.  U  .<_  ( S  .\/  T ) ) )  ->  ( ( S  .\/  T )  ./\  ( F  .\/  G ) )  =  ( ( F  .\/  G )  ./\  W )
 )
 
Theoremcdleme16g 29377 Part of proof of Lemma E in [Crawley] p. 113, 3rd paragraph on p. 114, Eq. (1).  F and  G represent f(s) and f(t) respectively. We show, in their notation, (s 
\/ t)  /\ w=(f(s)  \/ f(t))  /\ w. (Contributed by NM, 11-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   =>    |-  ( ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  (
 ( S  e.  A  /\  -.  S  .<_  W ) 
 /\  ( T  e.  A  /\  -.  T  .<_  W )  /\  ( P  =/=  Q  /\  S  =/=  T ) )  /\  ( -.  S  .<_  ( P 
 .\/  Q )  /\  -.  T  .<_  ( P  .\/  Q )  /\  -.  U  .<_  ( S  .\/  T ) ) )  ->  ( ( S  .\/  T )  ./\  W )  =  ( ( F  .\/  G )  ./\  W )
 )
 
Theoremcdleme16 29378 Part of proof of Lemma E in [Crawley] p. 113, conclusion of 3rd paragraph on p. 114.  F and  G represent f(s) and f(t) respectively. We show, in their notation, (s  \/ t)  /\ w=(f(s)  \/ f(t))  /\ w, whether or not u  <_ s  \/ t. (Contributed by NM, 11-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   =>    |-  ( ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  (
 ( S  e.  A  /\  -.  S  .<_  W ) 
 /\  ( T  e.  A  /\  -.  T  .<_  W )  /\  ( P  =/=  Q  /\  S  =/=  T ) )  /\  ( -.  S  .<_  ( P 
 .\/  Q )  /\  -.  T  .<_  ( P  .\/  Q ) ) )  ->  ( ( S  .\/  T )  ./\  W )  =  ( ( F  .\/  G )  ./\  W )
 )
 
Theoremcdleme17a 29379 Part of proof of Lemma E in [Crawley] p. 114, first part of 4th paragraph.  F,  G, and  C represent f(s), fs(p), and s1 respectively. We show, in their notation, fs(p)=(p  \/ q)  /\ (q  \/ s1). (Contributed by NM, 11-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  C  =  ( ( P  .\/  S )  ./\  W )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( ( P  e.  A  /\  -.  P  .<_  W )  /\  Q  e.  A  /\  ( S  e.  A  /\  -.  S  .<_  W ) )  /\  -.  S  .<_  ( P  .\/  Q ) )  ->  G  =  ( ( P  .\/  Q )  ./\  ( Q  .\/  C ) ) )
 
Theoremcdleme17b 29380 Lemma leading to cdleme17c 29381. (Contributed by NM, 11-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  C  =  ( ( P  .\/  S )  ./\  W )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  S  e.  A  /\  -.  S  .<_  ( P 
 .\/  Q ) ) ) 
 ->  -.  C  .<_  ( P 
 .\/  Q ) )
 
Theoremcdleme17c 29381 Part of proof of Lemma E in [Crawley] p. 114, first part of 4th paragraph.  C represents s1. We show, in their notation, (p  \/ q)  /\ (q  \/ s1)=q. (Contributed by NM, 11-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  C  =  ( ( P  .\/  S )  ./\  W )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  S  e.  A  /\  -.  S  .<_  ( P 
 .\/  Q ) ) ) 
 ->  ( ( P  .\/  Q )  ./\  ( Q  .\/  C ) )  =  Q )
 
Theoremcdleme17d1 29382 Part of proof of Lemma E in [Crawley] p. 114, first part of 4th paragraph.  F,  G represent f(s), fs(p) respectively. We show, in their notation, fs(p)=q. (Contributed by NM, 11-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  (
 ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  Q  e.  A  /\  ( S  e.  A  /\  -.  S  .<_  W ) )  /\  -.  S  .<_  ( P  .\/  Q ) )  ->  G  =  Q )
 
Theoremcdleme0nex 29383* Part of proof of Lemma E in [Crawley] p. 114, 4th line of 4th paragraph. Whenever (in their terminology) p  \/ q/0 (i.e. the sublattice from 0 to p  \/ q) contains precisely three atoms, any atom not under w must equal either p or q. (In case of 3 atoms, one of them must be u - see cdleme0a 29304- which is under w, so the only 2 left not under w are p and q themselves.) Note that by cvlsupr2 28437, our  ( P  .\/  r )  =  ( Q  .\/  r ) is a shorter way to express  r  =/=  P  /\  r  =/=  Q  /\  r  .<_  ( P 
.\/  Q ). Thus the negated existential condition states there are no atoms different from p or q that are also not under w. (Contributed by NM, 12-Nov-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  A  =  (
 Atoms `  K )   =>    |-  ( ( ( K  e.  HL  /\  R  .<_  ( P  .\/  Q )  /\  -.  E. r  e.  A  ( -.  r  .<_  W  /\  ( P  .\/  r )  =  ( Q  .\/  r ) ) ) 
 /\  ( P  e.  A  /\  Q  e.  A  /\  P  =/=  Q ) 
 /\  ( R  e.  A  /\  -.  R  .<_  W ) )  ->  ( R  =  P  \/  R  =  Q )
 )
 
Theoremcdleme18a 29384 Part of proof of Lemma E in [Crawley] p. 114, 2nd sentence of 4th paragraph.  F,  G represent f(s), fs(q) respectively. We show  -. fs(q)  <_ w. (Contributed by NM, 12-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  ( ( Q  .\/  S )  ./\  W )
 ) )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  (
 ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W )  /\  ( S  e.  A  /\  -.  S  .<_  W ) ) 
 /\  ( P  =/=  Q 
 /\  -.  S  .<_  ( P  .\/  Q )
 ) )  ->  -.  G  .<_  W )
 
Theoremcdleme18b 29385 Part of proof of Lemma E in [Crawley] p. 114, 2nd sentence of 4th paragraph.  F,  G represent f(s), fs(q) respectively. We show  -. fs(q)  =/= q. (Contributed by NM, 12-Oct-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  ( ( Q  .\/  S )  ./\  W )
 ) )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  (
 ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W )  /\  ( S  e.  A  /\  -.  S  .<_  W ) ) 
 /\  ( P  =/=  Q 
 /\  -.  S  .<_  ( P  .\/  Q )
 ) )  ->  G  =/=  Q )
 
Theoremcdleme18c 29386* Part of proof of Lemma E in [Crawley] p. 114, 2nd sentence of 4th paragraph.  F,  G represent f(s), fs(q) respectively. We show  -. fs(q) = p whenever p  \/ q has three atoms under it (implied by the negated existential condition). (Contributed by NM, 10-Nov-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  ( ( Q  .\/  S )  ./\  W )
 ) )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  (
 ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W )  /\  ( S  e.  A  /\  -.  S  .<_  W ) ) 
 /\  ( P  =/=  Q 
 /\  -.  S  .<_  ( P  .\/  Q )  /\  -.  E. r  e.  A  ( -.  r  .<_  W  /\  ( P 
 .\/  r )  =  ( Q  .\/  r
 ) ) ) ) 
 ->  G  =  P )
 
Theoremcdleme22gb 29387 Utility lemma for Lemma E in [Crawley] p. 115. (Contributed by NM, 5-Dec-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  ( ( R  .\/  S )  ./\  W )
 ) )   &    |-  B  =  (
 Base `  K )   =>    |-  ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  Q  e.  A ) 
 /\  ( R  e.  A  /\  S  e.  A ) )  ->  G  e.  B )
 
Theoremcdleme18d 29388* Part of proof of Lemma E in [Crawley] p. 114, 4th sentence of 4th paragraph.  F,  G,  D,  E represent f(s), fs(r), f(t), ft(r) respectively. We show fs(r)=ft(r) for all possible r (which must equal p or q in the case of exactly 3 atoms in p  \/ q/0 i.e. when  -.  E. r  e.  A...). (Contributed by NM, 12-Nov-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( P  .\/  Q )  ./\  ( F  .\/  ( ( R  .\/  S )  ./\  W )
 ) )   &    |-  D  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   &    |-  E  =  ( ( P  .\/  Q )  ./\  ( D  .\/  ( ( R  .\/  T )  ./\  W )
 ) )   =>    |-  ( ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W ) 
 /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  (
 ( R  e.  A  /\  -.  R  .<_  W ) 
 /\  ( S  e.  A  /\  -.  S  .<_  W )  /\  ( T  e.  A  /\  -.  T  .<_  W ) ) 
 /\  ( P  =/=  Q 
 /\  ( R  .<_  ( P  .\/  Q )  /\  -.  S  .<_  ( P 
 .\/  Q )  /\  -.  T  .<_  ( P  .\/  Q ) )  /\  -.  E. r  e.  A  ( -.  r  .<_  W  /\  ( P  .\/  r )  =  ( Q  .\/  r ) ) ) )  ->  G  =  E )
 
Theoremcdlemesner 29389 Part of proof of Lemma E in [Crawley] p. 113. Utility lemma. (Contributed by NM, 13-Nov-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  A  =  (
 Atoms `  K )   &    |-  H  =  ( LHyp `  K )   =>    |-  (
 ( K  e.  HL  /\  ( R  e.  A  /\  S  e.  A ) 
 /\  ( R  .<_  ( P  .\/  Q )  /\  -.  S  .<_  ( P 
 .\/  Q ) ) ) 
 ->  S  =/=  R )
 
Theoremcdlemedb 29390 Part of proof of Lemma E in [Crawley] p. 113. Utility lemma.  D represents s2. (Contributed by NM, 20-Nov-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  D  =  ( ( R  .\/  S )  ./\  W )   &    |-  B  =  ( Base `  K )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( R  e.  A  /\  S  e.  A ) )  ->  D  e.  B )
 
Theoremcdlemeda 29391 Part of proof of Lemma E in [Crawley] p. 113. Utility lemma.  D represents s2. (Contributed by NM, 13-Nov-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  D  =  ( ( R  .\/  S )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( S  e.  A  /\  -.  S  .<_  W )  /\  ( R  e.  A  /\  R  .<_  ( P  .\/  Q )  /\  -.  S  .<_  ( P  .\/  Q )
 ) )  ->  D  e.  A )
 
Theoremcdlemednpq 29392 Part of proof of Lemma E in [Crawley] p. 113. Utility lemma.  D represents s2. (Contributed by NM, 18-Nov-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  D  =  ( ( R  .\/  S )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  Q  e.  A  /\  ( R  e.  A  /\  -.  R  .<_  W ) )  /\  ( ( S  e.  A  /\  -.  S  .<_  W )  /\  R  .<_  ( P  .\/  Q )  /\  -.  S  .<_  ( P  .\/  Q ) ) )  ->  -.  D  .<_  ( P  .\/  Q ) )
 
TheoremcdlemednuN 29393 Part of proof of Lemma E in [Crawley] p. 113. Utility lemma.  D represents s2. (Contributed by NM, 18-Nov-2012.) (New usage is discouraged.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  D  =  ( ( R  .\/  S )  ./\  W )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  Q  e.  A  /\  ( R  e.  A  /\  -.  R  .<_  W ) )  /\  ( ( S  e.  A  /\  -.  S  .<_  W )  /\  R  .<_  ( P  .\/  Q )  /\  -.  S  .<_  ( P  .\/  Q ) ) )  ->  D  =/=  U )
 
Theoremcdleme20zN 29394 Part of proof of Lemma E in [Crawley] p. 113. Utility lemma. (Contributed by NM, 17-Nov-2012.) (New usage is discouraged.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   =>    |-  (
 ( K  e.  HL  /\  ( R  e.  A  /\  S  e.  A  /\  T  e.  A )  /\  ( S  =/=  T  /\  -.  R  .<_  ( S 
 .\/  T ) ) ) 
 ->  ( ( S  .\/  R )  ./\  T )  =  ( 0. `  K ) )
 
Theoremcdleme20y 29395 Part of proof of Lemma E in [Crawley] p. 113. Utility lemma. (Contributed by NM, 17-Nov-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   =>    |-  (
 ( K  e.  HL  /\  ( R  e.  A  /\  S  e.  A  /\  T  e.  A )  /\  ( S  =/=  T  /\  -.  R  .<_  ( S 
 .\/  T ) ) ) 
 ->  ( ( S  .\/  R )  ./\  ( T  .\/  R ) )  =  R )
 
Theoremcdleme19a 29396 Part of proof of Lemma E in [Crawley] p. 113, 5th paragraph on p. 114, 1st line.  D represents s2. In their notation, we prove that if r  <_ s  \/ t, then s2=(s  \/ t)  /\ w. (Contributed by NM, 13-Nov-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   &    |-  D  =  ( ( R  .\/  S )  ./\  W )   &    |-  Y  =  ( ( R  .\/  T )  ./\  W )   =>    |-  (
 ( K  e.  HL  /\  ( R  e.  A  /\  S  e.  A  /\  T  e.  A )  /\  ( R  .<_  ( P 
 .\/  Q )  /\  -.  S  .<_  ( P  .\/  Q )  /\  R  .<_  ( S  .\/  T )
 ) )  ->  D  =  ( ( S  .\/  T )  ./\  W )
 )
 
Theoremcdleme19b 29397 Part of proof of Lemma E in [Crawley] p. 113, 5th paragraph on p. 114, 1st line.  D,  F,  G represent s2, f(s), f(t). In their notation, we prove that if r 
<_ s  \/ t, then s2  <_ f(s)  \/ f(t). (Contributed by NM, 13-Nov-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   &    |-  D  =  ( ( R  .\/  S )  ./\  W )   &    |-  Y  =  ( ( R  .\/  T )  ./\  W )   =>    |-  (
 ( ( ( K  e.  HL  /\  W  e.  H )  /\  ( P  e.  A  /\  -.  P  .<_  W )  /\  ( Q  e.  A  /\  -.  Q  .<_  W ) )  /\  ( ( S  e.  A  /\  -.  S  .<_  W )  /\  ( T  e.  A  /\  -.  T  .<_  W ) 
 /\  R  e.  A )  /\  ( ( P  =/=  Q  /\  S  =/=  T )  /\  ( -.  S  .<_  ( P  .\/  Q )  /\  -.  T  .<_  ( P  .\/  Q ) )  /\  ( R 
 .<_  ( P  .\/  Q )  /\  R  .<_  ( S 
 .\/  T ) ) ) )  ->  D  .<_  ( F  .\/  G )
 )
 
Theoremcdleme19c 29398 Part of proof of Lemma E in [Crawley] p. 113, 5th paragraph on p. 114, 1st line.  D,  F represent s2, f(s). We prove f(s)  =/= s2. (Contributed by NM, 13-Nov-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  S )  ./\  W )
 ) )   &    |-  G  =  ( ( T  .\/  U )  ./\  ( Q  .\/  ( ( P  .\/  T )  ./\  W )
 ) )   &    |-  D  =  ( ( R  .\/  S )  ./\  W )   &    |-  Y  =  ( ( R  .\/  T )  ./\  W )   =>    |-  (
 ( ( K  e.  HL  /\  W  e.  H )  /\  ( ( P  e.  A  /\  -.  P  .<_  W )  /\  ( Q  e.  A  /\  -.  Q  .<_  W ) 
 /\  ( S  e.  A  /\  -.  S  .<_  W ) )  /\  ( R  e.  A  /\  P  =/=  Q  /\  -.  S  .<_  ( P  .\/  Q ) ) )  ->  F  =/=  D )
 
Theoremcdleme19d 29399 Part of proof of Lemma E in [Crawley] p. 113, 5th paragraph on p. 114.  D,  F,  G represent s2, f(s), f(t). We prove f(s)  \/ s2 = f(s)  \/ f(t). (Contributed by NM, 14-Nov-2012.)
 |-  .<_  =  ( le `  K )   &    |- 
 .\/  =  ( join `  K )   &    |-  ./\  =  ( meet `  K )   &    |-  A  =  ( Atoms `  K )   &    |-  H  =  ( LHyp `  K )   &    |-  U  =  ( ( P  .\/  Q )  ./\  W )   &    |-  F  =  ( ( S  .\/  U )  ./\  ( Q