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 } ) | 
| 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 } ) |