Description: Equality theorem for transposition. (Contributed by Mario Carneiro, 10-Sep-2015)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | tposeq | |- ( F = G -> tpos F = tpos G ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | eqimss | |- ( F = G -> F C_ G ) | |
| 2 | tposss | |- ( F C_ G -> tpos F C_ tpos G ) | |
| 3 | 1 2 | syl | |- ( F = G -> tpos F C_ tpos G ) | 
| 4 | eqimss2 | |- ( F = G -> G C_ F ) | |
| 5 | tposss | |- ( G C_ F -> tpos G C_ tpos F ) | |
| 6 | 4 5 | syl | |- ( F = G -> tpos G C_ tpos F ) | 
| 7 | 3 6 | eqssd | |- ( F = G -> tpos F = tpos G ) |