Metamath Proof Explorer


Theorem eqnetrrid

Description: A chained equality inference for inequality. (Contributed by NM, 6-Jun-2012) (Proof shortened by Wolf Lammen, 19-Nov-2019)

Ref Expression
Hypotheses eqnetrrid.1
|- B = A
eqnetrrid.2
|- ( ph -> B =/= C )
Assertion eqnetrrid
|- ( ph -> A =/= C )

Proof

Step Hyp Ref Expression
1 eqnetrrid.1
 |-  B = A
2 eqnetrrid.2
 |-  ( ph -> B =/= C )
3 1 a1i
 |-  ( ph -> B = A )
4 3 2 eqnetrrd
 |-  ( ph -> A =/= C )