ILE Home Intuitionistic Logic Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  ILE Home  >  Th. List  >  19.21bbi Unicode version

Theorem 19.21bbi 1492
Description: Inference removing double quantifier. (Contributed by NM, 20-Apr-1994.)
Hypothesis
Ref Expression
19.21bbi.1  |-  ( ph  ->  A. x A. y ps )
Assertion
Ref Expression
19.21bbi  |-  ( ph  ->  ps )

Proof of Theorem 19.21bbi
StepHypRef Expression
1 19.21bbi.1 . . 3  |-  ( ph  ->  A. x A. y ps )
2119.21bi 1491 . 2  |-  ( ph  ->  A. y ps )
3219.21bi 1491 1  |-  ( ph  ->  ps )
Colors of variables: wff set class
Syntax hints:    -> wi 4   A.wal 1283
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-4 1441
This theorem is referenced by:  pocl  4066  funun  4974  fununi  4998  imain  5012
  Copyright terms: Public domain W3C validator