Metamath Proof Explorer


Theorem com4t

Description: Commutation of antecedents. Rotate twice. (Contributed by NM, 25-Apr-1994)

Ref Expression
Hypothesis com4.1 φψχθτ
Assertion com4t χθφψτ

Proof

Step Hyp Ref Expression
1 com4.1 φψχθτ
2 1 com4l ψχθφτ
3 2 com4l χθφψτ