Theorem r19.44mv 3462

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 2592	. 2 |- ( E. x e. A ( ph \/ ps ) <-> ( E. x e. A ph \/ E. x e. A ps ) )
2		r19.9rmv 3459	. . 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 1469   e. wcel 1481   E.wrex 2418

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 1424  ax-7 1425  ax-gen 1426  ax-ie1 1470  ax-ie2 1471  ax-8 1483  ax-4 1488  ax-17 1507  ax-i9 1511  ax-ial 1515  ax-ext 2122

This theorem depends on definitions:  df-bi 116  df-cleq 2133  df-clel 2136  df-rex 2423

This theorem is referenced by:  frecabcl  6304