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Description: The binary relation form of the singleton function. (Contributed by Scott Fenton, 4-Apr-2014) (Revised by Mario Carneiro, 19-Apr-2014)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | brsingle.1 | ||
| brsingle.2 | |||
| Assertion | brsingle |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | brsingle.1 | ||
| 2 | brsingle.2 | ||
| 3 | df-singleton | ||
| 4 | brxp | ||
| 5 | 1 2 4 | mpbir2an | |
| 6 | velsn | ||
| 7 | 1 | ideq | |
| 8 | 6 7 | bitr4i | |
| 9 | 1 2 3 5 8 | brtxpsd3 |