Theorem 3ancomb 981

Description: Commutation law for triple conjunction. (Contributed by NM, 21-Apr-1994.)

Assertion

Ref	Expression
3ancomb	|- ( ( ph /\ ps /\ ch ) <-> ( ph /\ ch /\ ps ) )

Proof of Theorem 3ancomb

Step	Hyp	Ref	Expression
1		3ancoma 980	. 2 |- ( ( ph /\ ps /\ ch ) <-> ( ps /\ ph /\ ch ) )
2		3anrot 978	. 2 |- ( ( ps /\ ph /\ ch ) <-> ( ph /\ ch /\ ps ) )
3	1, 2	bitri 183	1 |- ( ( ph /\ ps /\ ch ) <-> ( ph /\ ch /\ ps ) )

Syntax hints:   <-> wb 104   /\ w3a 973

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107

This theorem depends on definitions:  df-bi 116  df-3an 975

This theorem is referenced by:  3simpb  990  addcanprg  7578  elioore  9869  pcgcd  12282  xmetrtri  13170