Metamath Proof Explorer


Theorem eqtr4i

Description: An equality transitivity inference. (Contributed by NM, 26-May-1993)

Ref Expression
Hypotheses eqtr4i.1 ⊢ A = B
eqtr4i.2 ⊢ C = B
Assertion eqtr4i ⊢ A = C

Proof

Step Hyp Ref Expression
1 eqtr4i.1 ⊢ A = B
2 eqtr4i.2 ⊢ C = B
3 2 eqcomi ⊢ B = C
4 1 3 eqtri ⊢ A = C