ILE Home Intuitionistic Logic Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  ILE Home  >  Th. List  >  sbcex2 Structured version   GIF version

Theorem sbcex2 2806
Description: Move existential quantifier in and out of class substitution. (Contributed by NM, 21-May-2004.)
Assertion
Ref Expression
sbcex2 ([A / y]xφx[A / y]φ)
Distinct variable groups:   x,A   x,y
Allowed substitution hints:   φ(x,y)   A(y)

Proof of Theorem sbcex2
Dummy variable z is distinct from all other variables.
StepHypRef Expression
1 sbcex 2766 . 2 ([A / y]xφA V)
2 sbcex 2766 . . 3 ([A / y]φA V)
32exlimiv 1486 . 2 (x[A / y]φA V)
4 dfsbcq2 2761 . . 3 (z = A → ([z / y]xφ[A / y]xφ))
5 dfsbcq2 2761 . . . 4 (z = A → ([z / y]φ[A / y]φ))
65exbidv 1703 . . 3 (z = A → (x[z / y]φx[A / y]φ))
7 sbex 1877 . . 3 ([z / y]xφx[z / y]φ)
84, 6, 7vtoclbg 2608 . 2 (A V → ([A / y]xφx[A / y]φ))
91, 3, 8pm5.21nii 619 1 ([A / y]xφx[A / y]φ)
Colors of variables: wff set class
Syntax hints:  wb 98   = wceq 1242  wex 1378   wcel 1390  [wsb 1642  Vcvv 2551  [wsbc 2758
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-io 629  ax-5 1333  ax-7 1334  ax-gen 1335  ax-ie1 1379  ax-ie2 1380  ax-8 1392  ax-10 1393  ax-11 1394  ax-i12 1395  ax-bnd 1396  ax-4 1397  ax-17 1416  ax-i9 1420  ax-ial 1424  ax-i5r 1425  ax-ext 2019
This theorem depends on definitions:  df-bi 110  df-tru 1245  df-nf 1347  df-sb 1643  df-clab 2024  df-cleq 2030  df-clel 2033  df-nfc 2164  df-v 2553  df-sbc 2759
This theorem is referenced by:  csbdmg  4472
  Copyright terms: Public domain W3C validator