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Theorem con4bid 284

Description: A contraposition deduction. (Contributed by NM, 21-May-1994.)

Hypothesis

Ref	Expression
con4bid.1

Assertion

Ref	Expression
con4bid

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Proof of Theorem con4bid

Step	Hyp	Ref	Expression
1		con4bid.1	. . . 4
2	1	biimprd 214	. . 3
3	2	con4d 97	. 2
4	1	biimpd 198	. 2
5	3, 4	impcon4bid 196	1

Colors of variables: wff setvar class

Syntax hints:   wn 3   wi 4   wb 176

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8

This theorem depends on definitions:  df-bi 177

This theorem is referenced by:  notbid  285  notbi  286  had0  1403  necon4abid  2580  sbcne12g  3154  isomin  5496

Copyright terms: Public domain

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