Theorem alexnim 1580

Description: A relationship between two quantifiers and negation. (Contributed by Jim Kingdon, 27-Aug-2018.)

Assertion

Ref	Expression
alexnim	|- ( A. x E. y -. ph -> -. E. x A. y ph )

Proof of Theorem alexnim

Step	Hyp	Ref	Expression
1		exnalim 1578	. . 3 |- ( E. y -. ph -> -. A. y ph )
2	1	alimi 1385	. 2 |- ( A. x E. y -. ph -> A. x -. A. y ph )
3		alnex 1429	. 2 |- ( A. x -. A. y ph <-> -. E. x A. y ph )
4	2, 3	sylib 120	1 |- ( A. x E. y -. ph -> -. E. x A. y ph )

Syntax hints:   -. wn 3   -> wi 4   A.wal 1283   E.wex 1422

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-in1 577  ax-in2 578  ax-5 1377  ax-gen 1379  ax-ie1 1423  ax-ie2 1424  ax-4 1441  ax-17 1460  ax-ial 1468

This theorem depends on definitions:  df-bi 115  df-tru 1288  df-fal 1291  df-nf 1391

This theorem is referenced by:  nalset  3916  bj-nalset  10844