Metamath Proof Explorer


Theorem cmbri

Description: Binary relation expressing the commutes relation. Definition of commutes in Kalmbach p. 20. (Contributed by NM, 6-Aug-2004) (New usage is discouraged.)

Ref Expression
Hypotheses pjoml2.1 AC
pjoml2.2 BC
Assertion cmbri A𝐶BA=ABAB

Proof

Step Hyp Ref Expression
1 pjoml2.1 AC
2 pjoml2.2 BC
3 cmbr ACBCA𝐶BA=ABAB
4 1 2 3 mp2an A𝐶BA=ABAB