Theorem r19.44mv 3503

Description: Restricted version of Theorem 19.44 of [Margaris] p. 90. (Contributed by NM, 27-May-1998.)

Assertion

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

Distinct variable groups:   x, A   y, A   ps, x

Allowed substitution hints:   ph( x, y)   ps( y)

Proof of Theorem r19.44mv

Step	Hyp	Ref	Expression
1		r19.43 2624	. 2 |- ( E. x e. A ( ph \/ ps ) <-> ( E. x e. A ph \/ E. x e. A ps ) )
2		r19.9rmv 3500	. . 3 |- ( E. y y e. A -> ( ps <-> E. x e. A ps ) )
3	2	orbi2d 780	. 2 |- ( E. y y e. A -> ( ( E. x e. A ph \/ ps ) <-> ( E. x e. A ph \/ E. x e. A ps ) ) )
4	1, 3	bitr4id 198	1 |- ( E. y y e. A -> ( E. x e. A ( ph \/ ps ) <-> ( E. x e. A ph \/ ps ) ) )

Syntax hints:   -> wi 4   <-> wb 104   \/ wo 698   E.wex 1480   e. wcel 2136   E.wrex 2445

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-io 699  ax-5 1435  ax-7 1436  ax-gen 1437  ax-ie1 1481  ax-ie2 1482  ax-8 1492  ax-4 1498  ax-17 1514  ax-i9 1518  ax-ial 1522  ax-ext 2147

This theorem depends on definitions:  df-bi 116  df-cleq 2158  df-clel 2161  df-rex 2450

This theorem is referenced by:  frecabcl  6367