Theorem bj-axemptylem 13927

Description: Lemma for bj-axempty 13928 and bj-axempty2 13929. (Contributed by BJ, 25-Oct-2020.) (Proof modification is discouraged.) Use ax-nul 4115 instead. (New usage is discouraged.)

Assertion

Ref	Expression
bj-axemptylem	|- E. x A. y ( y e. x -> F. )

Distinct variable group:   x, y

Proof of Theorem bj-axemptylem

Dummy variable z is distinct from all other variables.

Step	Hyp	Ref	Expression
1		bdfal 13868	. . 3 |- BOUNDED F.
2	1	bdsep1 13920	. 2 |- E. x A. y ( y e. x <-> ( y e. z /\ F. ) )
3		biimp 117	. . . 4 |- ( ( y e. x <-> ( y e. z /\ F. ) ) -> ( y e. x -> ( y e. z /\ F. ) ) )
4		falimd 1363	. . . 4 |- ( ( y e. z /\ F. ) -> F. )
5	3, 4	syl6 33	. . 3 |- ( ( y e. x <-> ( y e. z /\ F. ) ) -> ( y e. x -> F. ) )
6	5	alimi 1448	. 2 |- ( A. y ( y e. x <-> ( y e. z /\ F. ) ) -> A. y ( y e. x -> F. ) )
7	2, 6	eximii 1595	1 |- E. x A. y ( y e. x -> F. )

Syntax hints:   -> wi 4   /\ wa 103   <-> wb 104   A.wal 1346   F. wfal 1353   E.wex 1485

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-in1 609  ax-in2 610  ax-5 1440  ax-gen 1442  ax-ie1 1486  ax-ie2 1487  ax-4 1503  ax-ial 1527  ax-bd0 13848  ax-bdim 13849  ax-bdn 13852  ax-bdeq 13855  ax-bdsep 13919

This theorem depends on definitions:  df-bi 116  df-tru 1351  df-fal 1354

This theorem is referenced by:  bj-axempty  13928  bj-axempty2  13929