Theorem ibd 167

Description: Deduction that converts a biconditional implied by one of its arguments, into an implication. (Contributed by NM, 26-Jun-2004.)

Hypothesis

Ref	Expression
ibd.1	|- ( ph -> ( ps -> ( ps <-> ch ) ) )

Assertion

Ref	Expression
ibd	|- ( ph -> ( ps -> ch ) )

Proof of Theorem ibd

Step	Hyp	Ref	Expression
1		ibd.1	. 2 |- ( ph -> ( ps -> ( ps <-> ch ) ) )
2		bi1 111	. 2 |- ( ( ps <-> ch ) -> ( ps -> ch ) )
3	1, 2	syli 33	1 |- ( ph -> ( ps -> ch ) )

Syntax hints:   -> wi 4   <-> wb 98

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99

This theorem depends on definitions:  df-bi 110

This theorem is referenced by:  pm5.21ndd  621  oibabs  800  sssnm  3525