This is an inofficial mirror of http://metamath.tirix.org for personal testing of a visualizer extension only.
Description: The range of the indicator function is a subset of RR . (Contributed by Thierry Arnoux, 14-Aug-2017)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | pr01ssre |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | 0re | ||
| 2 | 1re | ||
| 3 | prssi | ||
| 4 | 1 2 3 | mp2an |