Metamath Proof Explorer


Theorem eqtr2di

Description: An equality transitivity deduction. (Contributed by NM, 29-Mar-1998)

Ref Expression
Hypotheses eqtr2di.1 φ A = B
eqtr2di.2 B = C
Assertion eqtr2di φ C = A

Proof

Step Hyp Ref Expression
1 eqtr2di.1 φ A = B
2 eqtr2di.2 B = C
3 1 2 eqtrdi φ A = C
4 3 eqcomd φ C = A