Metamath Proof Explorer


Theorem bnj312

Description: /\ -manipulation. (Contributed by Jonathan Ben-Naim, 3-Jun-2011) (New usage is discouraged.)

Ref Expression
Assertion bnj312
|- ( ( ph /\ ps /\ ch /\ th ) <-> ( ps /\ ph /\ ch /\ th ) )

Proof

Step Hyp Ref Expression
1 3ancoma
 |-  ( ( ph /\ ps /\ ch ) <-> ( ps /\ ph /\ ch ) )
2 1 anbi1i
 |-  ( ( ( ph /\ ps /\ ch ) /\ th ) <-> ( ( ps /\ ph /\ ch ) /\ th ) )
3 df-bnj17
 |-  ( ( ph /\ ps /\ ch /\ th ) <-> ( ( ph /\ ps /\ ch ) /\ th ) )
4 df-bnj17
 |-  ( ( ps /\ ph /\ ch /\ th ) <-> ( ( ps /\ ph /\ ch ) /\ th ) )
5 2 3 4 3bitr4i
 |-  ( ( ph /\ ps /\ ch /\ th ) <-> ( ps /\ ph /\ ch /\ th ) )