Metamath Proof Explorer


Theorem eqtr4di

Description: An equality transitivity deduction. (Contributed by NM, 21-Jun-1993)

Ref Expression
Hypotheses eqtr4di.1 φ A = B
eqtr4di.2 C = B
Assertion eqtr4di φ A = C

Proof

Step Hyp Ref Expression
1 eqtr4di.1 φ A = B
2 eqtr4di.2 C = B
3 2 eqcomi B = C
4 1 3 eqtrdi φ A = C