Theorem atbiffatnnbalt 41081

Description: If a implies b, then a implies not not b. (Contributed by Jarvin Udandy, 29-Aug-2016.)

Assertion

Ref	Expression
atbiffatnnbalt	|- ( ( ph -> ps ) -> ( ph -> -. -. ps ) )

Proof of Theorem atbiffatnnbalt

Step	Hyp	Ref	Expression
1		atbiffatnnb 41079	1 |- ( ( ph -> ps ) -> ( ph -> -. -. ps ) )

Syntax hints:   -. wn 3   -> wi 4

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 197

This theorem is referenced by: (None)