Description: The open sets of a topological ordered space. (Contributed by Mario Carneiro, 12-Nov-2015) (Revised by AV, 9-Sep-2021)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | otpsstr.w | ||
| Assertion | otpstset | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | otpsstr.w | ||
| 2 | 1 | otpsstr | |
| 3 | tsetid | ||
| 4 | snsstp2 | ||
| 5 | 4 1 | sseqtrri | |
| 6 | 2 3 5 | strfv |