Theorem biantrud 288

Description: A wff is equivalent to its conjunction with truth. (Contributed by NM, 2-Aug-1994.) (Proof shortened by Wolf Lammen, 23-Oct-2013.)

Hypothesis

Ref	Expression
biantrud.1	|- ( ph -> ps )

Assertion

Ref	Expression
biantrud	|- ( ph -> ( ch <-> ( ch /\ ps ) ) )

Proof of Theorem biantrud

Step	Hyp	Ref	Expression
1		biantrud.1	. 2 |- ( ph -> ps )
2		iba 284	. 2 |- ( ps -> ( ch <-> ( ch /\ ps ) ) )
3	1, 2	syl 14	1 |- ( ph -> ( ch <-> ( ch /\ ps ) ) )

Syntax hints:   -> wi 4   /\ wa 97   <-> wb 98

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101

This theorem depends on definitions:  df-bi 110

This theorem is referenced by:  posng  4412  elrnmpt1  4585  fliftf  5439  elxp7  5797  eroveu  6197  reapltxor  7580  divap0b  7662  nnle1eq1  7938  nn0le0eq0  8210  nn0lt10b  8321  ioopos  8819