Metamath Proof Explorer


Theorem tpeq2d

Description: Equality theorem for unordered triples. (Contributed by NM, 22-Jun-2014)

Ref Expression
Hypothesis tpeq1d.1
|- ( ph -> A = B )
Assertion tpeq2d
|- ( ph -> { C , A , D } = { C , B , D } )

Proof

Step Hyp Ref Expression
1 tpeq1d.1
 |-  ( ph -> A = B )
2 tpeq2
 |-  ( A = B -> { C , A , D } = { C , B , D } )
3 1 2 syl
 |-  ( ph -> { C , A , D } = { C , B , D } )