Theorem 3anbi23d 1326

Description: Deduction conjoining and adding a conjunct to equivalences. (Contributed by NM, 8-Sep-2006.)

Hypotheses

Ref	Expression
3anbi12d.1	|- ( ph -> ( ps <-> ch ) )
3anbi12d.2	|- ( ph -> ( th <-> ta ) )

Assertion

Ref	Expression
3anbi23d	|- ( ph -> ( ( et /\ ps /\ th ) <-> ( et /\ ch /\ ta ) ) )

Proof of Theorem 3anbi23d

Step	Hyp	Ref	Expression
1		biidd 172	. 2 |- ( ph -> ( et <-> et ) )
2		3anbi12d.1	. 2 |- ( ph -> ( ps <-> ch ) )
3		3anbi12d.2	. 2 |- ( ph -> ( th <-> ta ) )
4	1, 2, 3	3anbi123d 1323	1 |- ( ph -> ( ( et /\ ps /\ th ) <-> ( et /\ ch /\ ta ) ) )

Syntax hints:   -> wi 4   <-> wb 105   /\ w3a 980

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108

This theorem depends on definitions:  df-bi 117  df-3an 982

This theorem is referenced by:  ltxrlt  8092  dfgcd2  12181  issubg3  13322  ivthreinc  14881