MPE Home Metamath Proof Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  MPE Home  >  Th. List  >  alexn Structured version   Unicode version

Theorem alexn 1709
Description: A relationship between two quantifiers and negation. (Contributed by NM, 18-Aug-1993.)
Assertion
Ref Expression
alexn  |-  ( A. x E. y  -.  ph  <->  -. 
E. x A. y ph )

Proof of Theorem alexn
StepHypRef Expression
1 exnal 1695 . . 3  |-  ( E. y  -.  ph  <->  -.  A. y ph )
21albii 1687 . 2  |-  ( A. x E. y  -.  ph  <->  A. x  -.  A. y ph )
3 alnex 1661 . 2  |-  ( A. x  -.  A. y ph  <->  -. 
E. x A. y ph )
42, 3bitri 252 1  |-  ( A. x E. y  -.  ph  <->  -. 
E. x A. y ph )
Colors of variables: wff setvar class
Syntax hints:   -. wn 3    <-> wb 187   A.wal 1435   E.wex 1659
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1665  ax-4 1678
This theorem depends on definitions:  df-bi 188  df-ex 1660
This theorem is referenced by:  2exnexn  1710  nalset  4553  kmlem2  8570  bj-nalset  31201
  Copyright terms: Public domain W3C validator