Description: Equality theorem for unordered triples. (Contributed by NM, 13-Sep-2011)
Ref | Expression | ||
---|---|---|---|
Assertion | tpeq2 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | preq2 | |
|
2 | 1 | uneq1d | |
3 | df-tp | |
|
4 | df-tp | |
|
5 | 2 3 4 | 3eqtr4g | |