Theorem r19.44av 1305

Description: One direction of a restricted quantifier version of Theorem 19.44 of [Margaris] p. 90. The other direction doesn't hold when A is empty.

Assertion

Ref	Expression
r19.44av	|- (E.x e. A (ph \/ ps) -> (E.x e. A ph \/ ps))

Distinct variable group(s):   ps,x

Proof of Theorem r19.44av

Step	Hyp	Ref	Expression
1		r19.43 1304	. 2 |- (E.x e. A (ph \/ ps) <-> (E.x e. A ph \/ E.x e. A ps))
2		idd 11	. . . 4 |- (x e. A -> (ps -> ps))
3	2	r19.23aiv 1284	. . 3 |- (E.x e. A ps -> ps)
4	3	orim2i 273	. 2 |- ((E.x e. A ph \/ E.x e. A ps) -> (E.x e. A ph \/ ps))
5	1, 4	sylbi 174	1 |- (E.x e. A (ph \/ ps) -> (E.x e. A ph \/ ps))

Syntax hints:   -> wi 2   \/ wo 195   e. wcel 1092  E.wrex 1202

This theorem was proved from axioms:  ax-1 3  ax-2 4  ax-3 5  ax-mp 6  ax-4 673  ax-5 674  ax-6 675  ax-gen 677  ax-17 925

This theorem depends on definitions:  df-bi 128  df-or 197  df-an 198  df-ex 679  df-rex 1206

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