Theorem bianabs 850

Description: Absorb a hypothesis into the second member of a biconditional. (Contributed by FL, 15-Feb-2007.)

Hypothesis

Ref	Expression
bianabs.1	|- (ph -> (ps <-> (ph /\ ch)))

Assertion

Ref	Expression
bianabs	|- (ph -> (ps <-> ch))

Proof of Theorem bianabs

Step	Hyp	Ref	Expression
1		bianabs.1	. 2 |- (ph -> (ps <-> (ph /\ ch)))
2		ibar 490	. 2 |- (ph -> (ch <-> (ph /\ ch)))
3	1, 2	bitr4d 247	1 |- (ph -> (ps <-> ch))

Syntax hints:   -> wi 4   <-> wb 176   /\ wa 358

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem depends on definitions:  df-bi 177  df-an 360

This theorem is referenced by:  ceqsrexv  2973  opelopab2a  4703  ov  5596  ovg  5602