Metamath Proof Explorer

Theorem dfifp4

Description: Alternate definition of the conditional operator for propositions. (Contributed by BJ, 30-Sep-2019)

Ref Expression
Assertion dfifp4 
|- ( if- ( ph , ps , ch ) <-> ( ( -. ph \/ ps ) /\ ( ph \/ ch ) ) )

Proof

Step Hyp Ref Expression
1 dfifp3 
 |-  ( if- ( ph , ps , ch ) <-> ( ( ph -> ps ) /\ ( ph \/ ch ) ) )
2 imor 
 |-  ( ( ph -> ps ) <-> ( -. ph \/ ps ) )
3 1 2 bianbi 
 |-  ( if- ( ph , ps , ch ) <-> ( ( -. ph \/ ps ) /\ ( ph \/ ch ) ) )