Theorem wcon 194

Description: Contraposition law.

Assertion

Ref	Expression
wcon	((a == b) == (a_|_ == b_|_)) = 1

Proof of Theorem wcon

Step	Hyp	Ref	Expression
1		conb 114	. 2 (a == b) = (a_|_ == b_|_)
2	1	bi1 110	1 ((a == b) == (a_|_ == b_|_)) = 1

Syntax hints:   = wb 1  _|_wn 4   == tb 5  1wt 9

This theorem was proved from axioms:  ax-a1 29  ax-a2 30  ax-a5 33  ax-r1 34  ax-r2 35  ax-r4 36  ax-r5 37

This theorem depends on definitions:  df-b 38  df-a 39  df-t 40  df-f 41

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