Theorem impbid21d 190

Description: Deduce an equivalence from two implications. (Contributed by Wolf Lammen, 12-May-2013.)

Hypotheses

Ref	Expression
impbid21d.1
impbid21d.2

Assertion

Ref	Expression
impbid21d

Proof of Theorem impbid21d

Step	Hyp	Ref	Expression
1		impbid21d.1	. . 3
2	1	a1i 11	. 2
3		impbid21d.2	. . 3
4	3	a1d 25	. 2
5	2, 4	impbidd 189	1

Syntax hints:  ->wi 4  <->wb 184

This theorem is referenced by:  impbid  191  pm5.1im  238  rp-fakenanass  37739

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 185