Theorem nfexOLD 2155

Description: Obsolete proof of nfex 2154 as of 16-Oct-2021. (Contributed by Mario Carneiro, 11-Aug-2016.) (Proof shortened by Wolf Lammen, 30-Dec-2017.) (Proof modification is discouraged.) (New usage is discouraged.)

Hypothesis

Ref	Expression
nfexOLD.1	|- F/ x ph

Assertion

Ref	Expression
nfexOLD	|- F/ x E. y ph

Proof of Theorem nfexOLD

Step	Hyp	Ref	Expression
1		nfexOLD.1	. . . 4 |- F/ x ph
2	1	nf5ri 2065	. . 3 |- ( ph -> A. x ph )
3	2	hbexOLD 2152	. 2 |- ( E. y ph -> A. x E. y ph )
4	3	nf5i 2024	1 |- F/ x E. y ph

Syntax hints:   E.wex 1704   F/wnf 1708

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-10 2019  ax-11 2034  ax-12 2047

This theorem depends on definitions:  df-bi 197  df-or 385  df-ex 1705  df-nf 1710

This theorem is referenced by: (None)