Metamath Proof Explorer


Theorem eqcomi

Description: Inference from commutative law for class equality. (Contributed by NM, 26-May-1993)

Ref Expression
Hypothesis eqcomi.1 ⊢ A = B
Assertion eqcomi ⊢ B = A

Proof

Step Hyp Ref Expression
1 eqcomi.1 ⊢ A = B
2 eqcom ⊢ A = B ↔ B = A
3 1 2 mpbi ⊢ B = A