P. 26 of Theorem List - Intuitionistic Logic Explorer

Theorem List for Intuitionistic Logic Explorer - 2501-2600   *Has distinct variable group(s)

Type	Label	Description
Statement
Theorem	raleqf 2501	Equality theorem for restricted universal quantifier, with bound-variable hypotheses instead of distinct variable restrictions. (Contributed by NM, 7-Mar-2004.) (Revised by Andrew Salmon, 11-Jul-2011.)
|- F/_ x A   &    |- F/_ x B   =>    |- ( A = B -> ( A. x e. A ph <-> A. x e. B ph ) )
Theorem	rexeqf 2502	Equality theorem for restricted existential quantifier, with bound-variable hypotheses instead of distinct variable restrictions. (Contributed by NM, 9-Oct-2003.) (Revised by Andrew Salmon, 11-Jul-2011.)
|- F/_ x A   &    |- F/_ x B   =>    |- ( A = B -> ( E. x e. A ph <-> E. x e. B ph ) )
Theorem	reueq1f 2503	Equality theorem for restricted uniqueness quantifier, with bound-variable hypotheses instead of distinct variable restrictions. (Contributed by NM, 5-Apr-2004.) (Revised by Andrew Salmon, 11-Jul-2011.)
|- F/_ x A   &    |- F/_ x B   =>    |- ( A = B -> ( E! x e. A ph <-> E! x e. B ph ) )
Theorem	rmoeq1f 2504	Equality theorem for restricted uniqueness quantifier, with bound-variable hypotheses instead of distinct variable restrictions. (Contributed by Alexander van der Vekens, 17-Jun-2017.)
|- F/_ x A   &    |- F/_ x B   =>    |- ( A = B -> ( E* x e. A ph <-> E* x e. B ph ) )
Theorem	raleq 2505*	Equality theorem for restricted universal quantifier. (Contributed by NM, 16-Nov-1995.)
|- ( A = B -> ( A. x e. A ph <-> A. x e. B ph ) )
Theorem	rexeq 2506*	Equality theorem for restricted existential quantifier. (Contributed by NM, 29-Oct-1995.)
|- ( A = B -> ( E. x e. A ph <-> E. x e. B ph ) )
Theorem	reueq1 2507*	Equality theorem for restricted uniqueness quantifier. (Contributed by NM, 5-Apr-2004.)
|- ( A = B -> ( E! x e. A ph <-> E! x e. B ph ) )
Theorem	rmoeq1 2508*	Equality theorem for restricted uniqueness quantifier. (Contributed by Alexander van der Vekens, 17-Jun-2017.)
|- ( A = B -> ( E* x e. A ph <-> E* x e. B ph ) )
Theorem	raleqi 2509*	Equality inference for restricted universal qualifier. (Contributed by Paul Chapman, 22-Jun-2011.)
|- A = B   =>    |- ( A. x e. A ph <-> A. x e. B ph )
Theorem	rexeqi 2510*	Equality inference for restricted existential qualifier. (Contributed by Mario Carneiro, 23-Apr-2015.)
|- A = B   =>    |- ( E. x e. A ph <-> E. x e. B ph )
Theorem	raleqdv 2511*	Equality deduction for restricted universal quantifier. (Contributed by NM, 13-Nov-2005.)
|- ( ph -> A = B )   =>    |- ( ph -> ( A. x e. A ps <-> A. x e. B ps ) )
Theorem	rexeqdv 2512*	Equality deduction for restricted existential quantifier. (Contributed by NM, 14-Jan-2007.)
|- ( ph -> A = B )   =>    |- ( ph -> ( E. x e. A ps <-> E. x e. B ps ) )
Theorem	raleqbi1dv 2513*	Equality deduction for restricted universal quantifier. (Contributed by NM, 16-Nov-1995.)
|- ( A = B -> ( ph <-> ps ) )   =>    |- ( A = B -> ( A. x e. A ph <-> A. x e. B ps ) )
Theorem	rexeqbi1dv 2514*	Equality deduction for restricted existential quantifier. (Contributed by NM, 18-Mar-1997.)
|- ( A = B -> ( ph <-> ps ) )   =>    |- ( A = B -> ( E. x e. A ph <-> E. x e. B ps ) )
Theorem	reueqd 2515*	Equality deduction for restricted uniqueness quantifier. (Contributed by NM, 5-Apr-2004.)
|- ( A = B -> ( ph <-> ps ) )   =>    |- ( A = B -> ( E! x e. A ph <-> E! x e. B ps ) )
Theorem	rmoeqd 2516*	Equality deduction for restricted uniqueness quantifier. (Contributed by Alexander van der Vekens, 17-Jun-2017.)
|- ( A = B -> ( ph <-> ps ) )   =>    |- ( A = B -> ( E* x e. A ph <-> E* x e. B ps ) )
Theorem	raleqbidv 2517*	Equality deduction for restricted universal quantifier. (Contributed by NM, 6-Nov-2007.)
|- ( ph -> A = B )   &    |- ( ph -> ( ps <-> ch ) )   =>    |- ( ph -> ( A. x e. A ps <-> A. x e. B ch ) )
Theorem	rexeqbidv 2518*	Equality deduction for restricted universal quantifier. (Contributed by NM, 6-Nov-2007.)
|- ( ph -> A = B )   &    |- ( ph -> ( ps <-> ch ) )   =>    |- ( ph -> ( E. x e. A ps <-> E. x e. B ch ) )
Theorem	raleqbidva 2519*	Equality deduction for restricted universal quantifier. (Contributed by Mario Carneiro, 5-Jan-2017.)
|- ( ph -> A = B )   &    |- ( ( ph /\ x e. A ) -> ( ps <-> ch ) )   =>    |- ( ph -> ( A. x e. A ps <-> A. x e. B ch ) )
Theorem	rexeqbidva 2520*	Equality deduction for restricted universal quantifier. (Contributed by Mario Carneiro, 5-Jan-2017.)
|- ( ph -> A = B )   &    |- ( ( ph /\ x e. A ) -> ( ps <-> ch ) )   =>    |- ( ph -> ( E. x e. A ps <-> E. x e. B ch ) )
Theorem	mormo 2521	Unrestricted "at most one" implies restricted "at most one". (Contributed by NM, 16-Jun-2017.)
|- ( E* x ph -> E* x e. A ph )
Theorem	reu5 2522	Restricted uniqueness in terms of "at most one." (Contributed by NM, 23-May-1999.) (Revised by NM, 16-Jun-2017.)
|- ( E! x e. A ph <-> ( E. x e. A ph /\ E* x e. A ph ) )
Theorem	reurex 2523	Restricted unique existence implies restricted existence. (Contributed by NM, 19-Aug-1999.)
|- ( E! x e. A ph -> E. x e. A ph )
Theorem	reurmo 2524	Restricted existential uniqueness implies restricted "at most one." (Contributed by NM, 16-Jun-2017.)
|- ( E! x e. A ph -> E* x e. A ph )
Theorem	rmo5 2525	Restricted "at most one" in term of uniqueness. (Contributed by NM, 16-Jun-2017.)
|- ( E* x e. A ph <-> ( E. x e. A ph -> E! x e. A ph ) )
Theorem	nrexrmo 2526	Nonexistence implies restricted "at most one". (Contributed by NM, 17-Jun-2017.)
|- ( -. E. x e. A ph -> E* x e. A ph )
Theorem	cbvralf 2527	Rule used to change bound variables, using implicit substitution. (Contributed by NM, 7-Mar-2004.) (Revised by Mario Carneiro, 9-Oct-2016.)
|- F/_ x A   &    |- F/_ y A   &    |- F/ y ph   &    |- F/ x ps   &    |- ( x = y -> ( ph <-> ps ) )   =>    |- ( A. x e. A ph <-> A. y e. A ps )
Theorem	cbvrexf 2528	Rule used to change bound variables, using implicit substitution. (Contributed by FL, 27-Apr-2008.) (Revised by Mario Carneiro, 9-Oct-2016.) (Proof rewritten by Jim Kingdon, 10-Jun-2018.)
|- F/_ x A   &    |- F/_ y A   &    |- F/ y ph   &    |- F/ x ps   &    |- ( x = y -> ( ph <-> ps ) )   =>    |- ( E. x e. A ph <-> E. y e. A ps )
Theorem	cbvral 2529*	Rule used to change bound variables, using implicit substitution. (Contributed by NM, 31-Jul-2003.)
|- F/ y ph   &    |- F/ x ps   &    |- ( x = y -> ( ph <-> ps ) )   =>    |- ( A. x e. A ph <-> A. y e. A ps )
Theorem	cbvrex 2530*	Rule used to change bound variables, using implicit substitution. (Contributed by NM, 31-Jul-2003.) (Proof shortened by Andrew Salmon, 8-Jun-2011.)
|- F/ y ph   &    |- F/ x ps   &    |- ( x = y -> ( ph <-> ps ) )   =>    |- ( E. x e. A ph <-> E. y e. A ps )
Theorem	cbvreu 2531*	Change the bound variable of a restricted uniqueness quantifier using implicit substitution. (Contributed by Mario Carneiro, 15-Oct-2016.)
|- F/ y ph   &    |- F/ x ps   &    |- ( x = y -> ( ph <-> ps ) )   =>    |- ( E! x e. A ph <-> E! y e. A ps )
Theorem	cbvrmo 2532*	Change the bound variable of restricted "at most one" using implicit substitution. (Contributed by NM, 16-Jun-2017.)
|- F/ y ph   &    |- F/ x ps   &    |- ( x = y -> ( ph <-> ps ) )   =>    |- ( E* x e. A ph <-> E* y e. A ps )
Theorem	cbvralv 2533*	Change the bound variable of a restricted universal quantifier using implicit substitution. (Contributed by NM, 28-Jan-1997.)
|- ( x = y -> ( ph <-> ps ) )   =>    |- ( A. x e. A ph <-> A. y e. A ps )
Theorem	cbvrexv 2534*	Change the bound variable of a restricted existential quantifier using implicit substitution. (Contributed by NM, 2-Jun-1998.)
|- ( x = y -> ( ph <-> ps ) )   =>    |- ( E. x e. A ph <-> E. y e. A ps )
Theorem	cbvreuv 2535*	Change the bound variable of a restricted uniqueness quantifier using implicit substitution. (Contributed by NM, 5-Apr-2004.) (Revised by Mario Carneiro, 15-Oct-2016.)
|- ( x = y -> ( ph <-> ps ) )   =>    |- ( E! x e. A ph <-> E! y e. A ps )
Theorem	cbvrmov 2536*	Change the bound variable of a restricted uniqueness quantifier using implicit substitution. (Contributed by Alexander van der Vekens, 17-Jun-2017.)
|- ( x = y -> ( ph <-> ps ) )   =>    |- ( E* x e. A ph <-> E* y e. A ps )
Theorem	cbvraldva2 2537*	Rule used to change the bound variable in a restricted universal quantifier with implicit substitution which also changes the quantifier domain. Deduction form. (Contributed by David Moews, 1-May-2017.)
|- ( ( ph /\ x = y ) -> ( ps <-> ch ) )   &    |- ( ( ph /\ x = y ) -> A = B )   =>    |- ( ph -> ( A. x e. A ps <-> A. y e. B ch ) )
Theorem	cbvrexdva2 2538*	Rule used to change the bound variable in a restricted existential quantifier with implicit substitution which also changes the quantifier domain. Deduction form. (Contributed by David Moews, 1-May-2017.)
|- ( ( ph /\ x = y ) -> ( ps <-> ch ) )   &    |- ( ( ph /\ x = y ) -> A = B )   =>    |- ( ph -> ( E. x e. A ps <-> E. y e. B ch ) )
Theorem	cbvraldva 2539*	Rule used to change the bound variable in a restricted universal quantifier with implicit substitution. Deduction form. (Contributed by David Moews, 1-May-2017.)
|- ( ( ph /\ x = y ) -> ( ps <-> ch ) )   =>    |- ( ph -> ( A. x e. A ps <-> A. y e. A ch ) )
Theorem	cbvrexdva 2540*	Rule used to change the bound variable in a restricted existential quantifier with implicit substitution. Deduction form. (Contributed by David Moews, 1-May-2017.)
|- ( ( ph /\ x = y ) -> ( ps <-> ch ) )   =>    |- ( ph -> ( E. x e. A ps <-> E. y e. A ch ) )
Theorem	cbvral2v 2541*	Change bound variables of double restricted universal quantification, using implicit substitution. (Contributed by NM, 10-Aug-2004.)
|- ( x = z -> ( ph <-> ch ) )   &    |- ( y = w -> ( ch <-> ps ) )   =>    |- ( A. x e. A A. y e. B ph <-> A. z e. A A. w e. B ps )
Theorem	cbvrex2v 2542*	Change bound variables of double restricted universal quantification, using implicit substitution. (Contributed by FL, 2-Jul-2012.)
|- ( x = z -> ( ph <-> ch ) )   &    |- ( y = w -> ( ch <-> ps ) )   =>    |- ( E. x e. A E. y e. B ph <-> E. z e. A E. w e. B ps )
Theorem	cbvral3v 2543*	Change bound variables of triple restricted universal quantification, using implicit substitution. (Contributed by NM, 10-May-2005.)
|- ( x = w -> ( ph <-> ch ) )   &    |- ( y = v -> ( ch <-> th ) )   &    |- ( z = u -> ( th <-> ps ) )   =>    |- ( A. x e. A A. y e. B A. z e. C ph <-> A. w e. A A. v e. B A. u e. C ps )
Theorem	cbvralsv 2544*	Change bound variable by using a substitution. (Contributed by NM, 20-Nov-2005.) (Revised by Andrew Salmon, 11-Jul-2011.)
|- ( A. x e. A ph <-> A. y e. A [ y / x ] ph )
Theorem	cbvrexsv 2545*	Change bound variable by using a substitution. (Contributed by NM, 2-Mar-2008.) (Revised by Andrew Salmon, 11-Jul-2011.)
|- ( E. x e. A ph <-> E. y e. A [ y / x ] ph )
Theorem	sbralie 2546*	Implicit to explicit substitution that swaps variables in a quantified expression. (Contributed by NM, 5-Sep-2004.)
|- ( x = y -> ( ph <-> ps ) )   =>    |- ( [ x / y ] A. x e. y ph <-> A. y e. x ps )
Theorem	rabbiia 2547	Equivalent wff's yield equal restricted class abstractions (inference rule). (Contributed by NM, 22-May-1999.)
|- ( x e. A -> ( ph <-> ps ) )   =>    |- { x e. A | ph } = { x e. A | ps }
Theorem	rabbidva 2548*	Equivalent wff's yield equal restricted class abstractions (deduction rule). (Contributed by NM, 28-Nov-2003.)
|- ( ( ph /\ x e. A ) -> ( ps <-> ch ) )   =>    |- ( ph -> { x e. A | ps } = { x e. A | ch } )
Theorem	rabbidv 2549*	Equivalent wff's yield equal restricted class abstractions (deduction rule). (Contributed by NM, 10-Feb-1995.)
|- ( ph -> ( ps <-> ch ) )   =>    |- ( ph -> { x e. A | ps } = { x e. A | ch } )
Theorem	rabeqf 2550	Equality theorem for restricted class abstractions, with bound-variable hypotheses instead of distinct variable restrictions. (Contributed by NM, 7-Mar-2004.)
|- F/_ x A   &    |- F/_ x B   =>    |- ( A = B -> { x e. A | ph } = { x e. B | ph } )
Theorem	rabeq 2551*	Equality theorem for restricted class abstractions. (Contributed by NM, 15-Oct-2003.)
|- ( A = B -> { x e. A | ph } = { x e. B | ph } )
Theorem	rabeqbidv 2552*	Equality of restricted class abstractions. (Contributed by Jeff Madsen, 1-Dec-2009.)
|- ( ph -> A = B )   &    |- ( ph -> ( ps <-> ch ) )   =>    |- ( ph -> { x e. A | ps } = { x e. B | ch } )
Theorem	rabeqbidva 2553*	Equality of restricted class abstractions. (Contributed by Mario Carneiro, 26-Jan-2017.)
|- ( ph -> A = B )   &    |- ( ( ph /\ x e. A ) -> ( ps <-> ch ) )   =>    |- ( ph -> { x e. A | ps } = { x e. B | ch } )
Theorem	rabeq2i 2554	Inference rule from equality of a class variable and a restricted class abstraction. (Contributed by NM, 16-Feb-2004.)
|- A = { x e. B | ph }   =>    |- ( x e. A <-> ( x e. B /\ ph ) )
Theorem	cbvrab 2555	Rule to change the bound variable in a restricted class abstraction, using implicit substitution. This version has bound-variable hypotheses in place of distinct variable conditions. (Contributed by Andrew Salmon, 11-Jul-2011.) (Revised by Mario Carneiro, 9-Oct-2016.)
|- F/_ x A   &    |- F/_ y A   &    |- F/ y ph   &    |- F/ x ps   &    |- ( x = y -> ( ph <-> ps ) )   =>    |- { x e. A | ph } = { y e. A | ps }
Theorem	cbvrabv 2556*	Rule to change the bound variable in a restricted class abstraction, using implicit substitution. (Contributed by NM, 26-May-1999.)
|- ( x = y -> ( ph <-> ps ) )   =>    |- { x e. A | ph } = { y e. A | ps }
2.1.6  The universal class
Syntax	cvv 2557	Extend class notation to include the universal class symbol.
class _V
Theorem	vjust 2558	Soundness justification theorem for df-v 2559. (Contributed by Rodolfo Medina, 27-Apr-2010.)
|- { x | x = x } = { y | y = y }
Definition	df-v 2559	Define the universal class. Definition 5.20 of [TakeutiZaring] p. 21. Also Definition 2.9 of [Quine] p. 19. (Contributed by NM, 5-Aug-1993.)
|- _V = { x | x = x }
Theorem	vex 2560	All setvar variables are sets (see isset 2561). Theorem 6.8 of [Quine] p. 43. (Contributed by NM, 5-Aug-1993.)
|- x e. _V
Theorem	isset 2561*	Two ways to say " A is a set": A class A is a member of the universal class _V (see df-v 2559) if and only if the class A exists (i.e. there exists some set x equal to class A). Theorem 6.9 of [Quine] p. 43. Notational convention: We will use the notational device " A e. _V " to mean " A is a set" very frequently, for example in uniex 4174. Note the when A is not a set, it is called a proper class. In some theorems, such as uniexg 4175, in order to shorten certain proofs we use the more general antecedent A e. V instead of A e. _V to mean " A is a set." Note that a constant is implicitly considered distinct from all variables. This is why _V is not included in the distinct variable list, even though df-clel 2036 requires that the expression substituted for B not contain x. (Also, the Metamath spec does not allow constants in the distinct variable list.) (Contributed by NM, 26-May-1993.)
|- ( A e. _V <-> E. x x = A )
Theorem	issetf 2562	A version of isset that does not require x and A to be distinct. (Contributed by Andrew Salmon, 6-Jun-2011.) (Revised by Mario Carneiro, 10-Oct-2016.)
|- F/_ x A   =>    |- ( A e. _V <-> E. x x = A )
Theorem	isseti 2563*	A way to say " A is a set" (inference rule). (Contributed by NM, 5-Aug-1993.)
|- A e. _V   =>    |- E. x x = A
Theorem	issetri 2564*	A way to say " A is a set" (inference rule). (Contributed by NM, 5-Aug-1993.)
|- E. x x = A   =>    |- A e. _V
Theorem	eqvisset 2565	A class equal to a variable is a set. Note the absence of dv condition, contrary to isset 2561 and issetri 2564. (Contributed by BJ, 27-Apr-2019.)
|- ( x = A -> A e. _V )
Theorem	elex 2566	If a class is a member of another class, it is a set. Theorem 6.12 of [Quine] p. 44. (Contributed by NM, 5-Aug-1993.) (Proof shortened by Andrew Salmon, 8-Jun-2011.)
|- ( A e. B -> A e. _V )
Theorem	elexi 2567	If a class is a member of another class, it is a set. (Contributed by NM, 11-Jun-1994.)
|- A e. B   =>    |- A e. _V
Theorem	elisset 2568*	An element of a class exists. (Contributed by NM, 1-May-1995.)
|- ( A e. V -> E. x x = A )
Theorem	elex22 2569*	If two classes each contain another class, then both contain some set. (Contributed by Alan Sare, 24-Oct-2011.)
|- ( ( A e. B /\ A e. C ) -> E. x ( x e. B /\ x e. C ) )
Theorem	elex2 2570*	If a class contains another class, then it contains some set. (Contributed by Alan Sare, 25-Sep-2011.)
|- ( A e. B -> E. x x e. B )
Theorem	ralv 2571	A universal quantifier restricted to the universe is unrestricted. (Contributed by NM, 26-Mar-2004.)
|- ( A. x e. _V ph <-> A. x ph )
Theorem	rexv 2572	An existential quantifier restricted to the universe is unrestricted. (Contributed by NM, 26-Mar-2004.)
|- ( E. x e. _V ph <-> E. x ph )
Theorem	reuv 2573	A uniqueness quantifier restricted to the universe is unrestricted. (Contributed by NM, 1-Nov-2010.)
|- ( E! x e. _V ph <-> E! x ph )
Theorem	rmov 2574	A uniqueness quantifier restricted to the universe is unrestricted. (Contributed by Alexander van der Vekens, 17-Jun-2017.)
|- ( E* x e. _V ph <-> E* x ph )
Theorem	rabab 2575	A class abstraction restricted to the universe is unrestricted. (Contributed by NM, 27-Dec-2004.) (Proof shortened by Andrew Salmon, 8-Jun-2011.)
|- { x e. _V | ph } = { x | ph }
Theorem	ralcom4 2576*	Commutation of restricted and unrestricted universal quantifiers. (Contributed by NM, 26-Mar-2004.) (Proof shortened by Andrew Salmon, 8-Jun-2011.)
|- ( A. x e. A A. y ph <-> A. y A. x e. A ph )
Theorem	rexcom4 2577*	Commutation of restricted and unrestricted existential quantifiers. (Contributed by NM, 12-Apr-2004.) (Proof shortened by Andrew Salmon, 8-Jun-2011.)
|- ( E. x e. A E. y ph <-> E. y E. x e. A ph )
Theorem	rexcom4a 2578*	Specialized existential commutation lemma. (Contributed by Jeff Madsen, 1-Jun-2011.)
|- ( E. x E. y e. A ( ph /\ ps ) <-> E. y e. A ( ph /\ E. x ps ) )
Theorem	rexcom4b 2579*	Specialized existential commutation lemma. (Contributed by Jeff Madsen, 1-Jun-2011.)
|- B e. _V   =>    |- ( E. x E. y e. A ( ph /\ x = B ) <-> E. y e. A ph )
Theorem	ceqsalt 2580*	Closed theorem version of ceqsalg 2582. (Contributed by NM, 28-Feb-2013.) (Revised by Mario Carneiro, 10-Oct-2016.)
|- ( ( F/ x ps /\ A. x ( x = A -> ( ph <-> ps ) ) /\ A e. V ) -> ( A. x ( x = A -> ph ) <-> ps ) )
Theorem	ceqsralt 2581*	Restricted quantifier version of ceqsalt 2580. (Contributed by NM, 28-Feb-2013.) (Revised by Mario Carneiro, 10-Oct-2016.)
|- ( ( F/ x ps /\ A. x ( x = A -> ( ph <-> ps ) ) /\ A e. B ) -> ( A. x e. B ( x = A -> ph ) <-> ps ) )
Theorem	ceqsalg 2582*	A representation of explicit substitution of a class for a variable, inferred from an implicit substitution hypothesis. (Contributed by NM, 29-Oct-2003.) (Proof shortened by Andrew Salmon, 8-Jun-2011.)
|- F/ x ps   &    |- ( x = A -> ( ph <-> ps ) )   =>    |- ( A e. V -> ( A. x ( x = A -> ph ) <-> ps ) )
Theorem	ceqsal 2583*	A representation of explicit substitution of a class for a variable, inferred from an implicit substitution hypothesis. (Contributed by NM, 18-Aug-1993.)
|- F/ x ps   &    |- A e. _V   &    |- ( x = A -> ( ph <-> ps ) )   =>    |- ( A. x ( x = A -> ph ) <-> ps )
Theorem	ceqsalv 2584*	A representation of explicit substitution of a class for a variable, inferred from an implicit substitution hypothesis. (Contributed by NM, 18-Aug-1993.)
|- A e. _V   &    |- ( x = A -> ( ph <-> ps ) )   =>    |- ( A. x ( x = A -> ph ) <-> ps )
Theorem	ceqsralv 2585*	Restricted quantifier version of ceqsalv 2584. (Contributed by NM, 21-Jun-2013.)
|- ( x = A -> ( ph <-> ps ) )   =>    |- ( A e. B -> ( A. x e. B ( x = A -> ph ) <-> ps ) )
Theorem	gencl 2586*	Implicit substitution for class with embedded variable. (Contributed by NM, 17-May-1996.)
|- ( th <-> E. x ( ch /\ A = B ) )   &    |- ( A = B -> ( ph <-> ps ) )   &    |- ( ch -> ph )   =>    |- ( th -> ps )
Theorem	2gencl 2587*	Implicit substitution for class with embedded variable. (Contributed by NM, 17-May-1996.)
|- ( C e. S <-> E. x e. R A = C )   &    |- ( D e. S <-> E. y e. R B = D )   &    |- ( A = C -> ( ph <-> ps ) )   &    |- ( B = D -> ( ps <-> ch ) )   &    |- ( ( x e. R /\ y e. R ) -> ph )   =>    |- ( ( C e. S /\ D e. S ) -> ch )
Theorem	3gencl 2588*	Implicit substitution for class with embedded variable. (Contributed by NM, 17-May-1996.)
|- ( D e. S <-> E. x e. R A = D )   &    |- ( F e. S <-> E. y e. R B = F )   &    |- ( G e. S <-> E. z e. R C = G )   &    |- ( A = D -> ( ph <-> ps ) )   &    |- ( B = F -> ( ps <-> ch ) )   &    |- ( C = G -> ( ch <-> th ) )   &    |- ( ( x e. R /\ y e. R /\ z e. R ) -> ph )   =>    |- ( ( D e. S /\ F e. S /\ G e. S ) -> th )
Theorem	cgsexg 2589*	Implicit substitution inference for general classes. (Contributed by NM, 26-Aug-2007.)
|- ( x = A -> ch )   &    |- ( ch -> ( ph <-> ps ) )   =>    |- ( A e. V -> ( E. x ( ch /\ ph ) <-> ps ) )
Theorem	cgsex2g 2590*	Implicit substitution inference for general classes. (Contributed by NM, 26-Jul-1995.)
|- ( ( x = A /\ y = B ) -> ch )   &    |- ( ch -> ( ph <-> ps ) )   =>    |- ( ( A e. V /\ B e. W ) -> ( E. x E. y ( ch /\ ph ) <-> ps ) )
Theorem	cgsex4g 2591*	An implicit substitution inference for 4 general classes. (Contributed by NM, 5-Aug-1995.)
|- ( ( ( x = A /\ y = B ) /\ ( z = C /\ w = D ) ) -> ch )   &    |- ( ch -> ( ph <-> ps ) )   =>    |- ( ( ( A e. R /\ B e. S ) /\ ( C e. R /\ D e. S ) ) -> ( E. x E. y E. z E. w ( ch /\ ph ) <-> ps ) )
Theorem	ceqsex 2592*	Elimination of an existential quantifier, using implicit substitution. (Contributed by NM, 2-Mar-1995.) (Revised by Mario Carneiro, 10-Oct-2016.)
|- F/ x ps   &    |- A e. _V   &    |- ( x = A -> ( ph <-> ps ) )   =>    |- ( E. x ( x = A /\ ph ) <-> ps )
Theorem	ceqsexv 2593*	Elimination of an existential quantifier, using implicit substitution. (Contributed by NM, 2-Mar-1995.)
|- A e. _V   &    |- ( x = A -> ( ph <-> ps ) )   =>    |- ( E. x ( x = A /\ ph ) <-> ps )
Theorem	ceqsex2 2594*	Elimination of two existential quantifiers, using implicit substitution. (Contributed by Scott Fenton, 7-Jun-2006.)
|- F/ x ps   &    |- F/ y ch   &    |- A e. _V   &    |- B e. _V   &    |- ( x = A -> ( ph <-> ps ) )   &    |- ( y = B -> ( ps <-> ch ) )   =>    |- ( E. x E. y ( x = A /\ y = B /\ ph ) <-> ch )
Theorem	ceqsex2v 2595*	Elimination of two existential quantifiers, using implicit substitution. (Contributed by Scott Fenton, 7-Jun-2006.)
|- A e. _V   &    |- B e. _V   &    |- ( x = A -> ( ph <-> ps ) )   &    |- ( y = B -> ( ps <-> ch ) )   =>    |- ( E. x E. y ( x = A /\ y = B /\ ph ) <-> ch )
Theorem	ceqsex3v 2596*	Elimination of three existential quantifiers, using implicit substitution. (Contributed by NM, 16-Aug-2011.)
|- A e. _V   &    |- B e. _V   &    |- C e. _V   &    |- ( x = A -> ( ph <-> ps ) )   &    |- ( y = B -> ( ps <-> ch ) )   &    |- ( z = C -> ( ch <-> th ) )   =>    |- ( E. x E. y E. z ( ( x = A /\ y = B /\ z = C ) /\ ph ) <-> th )
Theorem	ceqsex4v 2597*	Elimination of four existential quantifiers, using implicit substitution. (Contributed by NM, 23-Sep-2011.)
|- A e. _V   &    |- B e. _V   &    |- C e. _V   &    |- D e. _V   &    |- ( x = A -> ( ph <-> ps ) )   &    |- ( y = B -> ( ps <-> ch ) )   &    |- ( z = C -> ( ch <-> th ) )   &    |- ( w = D -> ( th <-> ta ) )   =>    |- ( E. x E. y E. z E. w ( ( x = A /\ y = B ) /\ ( z = C /\ w = D ) /\ ph ) <-> ta )
Theorem	ceqsex6v 2598*	Elimination of six existential quantifiers, using implicit substitution. (Contributed by NM, 21-Sep-2011.)
|- A e. _V   &    |- B e. _V   &    |- C e. _V   &    |- D e. _V   &    |- E e. _V   &    |- F e. _V   &    |- ( x = A -> ( ph <-> ps ) )   &    |- ( y = B -> ( ps <-> ch ) )   &    |- ( z = C -> ( ch <-> th ) )   &    |- ( w = D -> ( th <-> ta ) )   &    |- ( v = E -> ( ta <-> et ) )   &    |- ( u = F -> ( et <-> ze ) )   =>    |- ( E. x E. y E. z E. w E. v E. u ( ( x = A /\ y = B /\ z = C ) /\ ( w = D /\ v = E /\ u = F ) /\ ph ) <-> ze )
Theorem	ceqsex8v 2599*	Elimination of eight existential quantifiers, using implicit substitution. (Contributed by NM, 23-Sep-2011.)
|- A e. _V   &    |- B e. _V   &    |- C e. _V   &    |- D e. _V   &    |- E e. _V   &    |- F e. _V   &    |- G e. _V   &    |- H e. _V   &    |- ( x = A -> ( ph <-> ps ) )   &    |- ( y = B -> ( ps <-> ch ) )   &    |- ( z = C -> ( ch <-> th ) )   &    |- ( w = D -> ( th <-> ta ) )   &    |- ( v = E -> ( ta <-> et ) )   &    |- ( u = F -> ( et <-> ze ) )   &    |- ( t = G -> ( ze <-> si ) )   &    |- ( s = H -> ( si <-> rh ) )   =>    |- ( E. x E. y E. z E. w E. v E. u E. t E. s ( ( ( x = A /\ y = B ) /\ ( z = C /\ w = D ) ) /\ ( ( v = E /\ u = F ) /\ ( t = G /\ s = H ) ) /\ ph ) <-> rh )
Theorem	gencbvex 2600*	Change of bound variable using implicit substitution. (Contributed by NM, 17-May-1996.) (Proof shortened by Andrew Salmon, 8-Jun-2011.)
|- A e. _V   &    |- ( A = y -> ( ph <-> ps ) )   &    |- ( A = y -> ( ch <-> th ) )   &    |- ( th <-> E. x ( ch /\ A = y ) )   =>    |- ( E. x ( ch /\ ph ) <-> E. y ( th /\ ps ) )