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 A C
pjoml2.2 B C
Assertion cmbri A 𝐶 B A = A B A B

Proof

Step Hyp Ref Expression
1 pjoml2.1 A C
2 pjoml2.2 B C
3 cmbr A C B C A 𝐶 B A = A B A B
4 1 2 3 mp2an A 𝐶 B A = A B A B