Description: Equality theorem for unordered triples. (Contributed by NM, 22-Jun-2014)
Ref | Expression | ||
---|---|---|---|
Hypotheses | tpeq1d.1 | |
|
tpeq123d.2 | |
||
tpeq123d.3 | |
||
Assertion | tpeq123d | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | tpeq1d.1 | |
|
2 | tpeq123d.2 | |
|
3 | tpeq123d.3 | |
|
4 | 1 | tpeq1d | |
5 | 2 | tpeq2d | |
6 | 3 | tpeq3d | |
7 | 4 5 6 | 3eqtrd | |