Theorem 3anbi23d 1255

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 228	. 2 |- (ph -> (et <-> et))
2		3anbi12d.1	. 2 |- (ph -> (ps <-> ch))
3		3anbi12d.2	. 2 |- (ph -> (th <-> ta))
4	1, 2, 3	3anbi123d 1252	1 |- (ph -> ((et /\ ps /\ th) <-> (et /\ ch /\ ta)))

Syntax hints:   -> wi 4   <-> wb 176   /\ w3a 934

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  df-3an 936

This theorem is referenced by:  sfineq2  4528  spaccl  6287  spacind  6288  nchoicelem3  6292