Metamath Proof Explorer

Theorem norasslem2

Description: This lemma specializes biimt suitably for the proof of norass . (Contributed by Wolf Lammen, 18-Dec-2023)

Ref Expression
Assertion norasslem2 
|- ( ph -> ( ps <-> ( ( ph \/ ch ) -> ps ) ) )

Proof

Step Hyp Ref Expression
1 biimt 
 |-  ( ( ph \/ ch ) -> ( ps <-> ( ( ph \/ ch ) -> ps ) ) )
2 1 orcs 
 |-  ( ph -> ( ps <-> ( ( ph \/ ch ) -> ps ) ) )