Description: Real closure of half. (Contributed by NM, 1-Jan-2006)
Ref | Expression | ||
---|---|---|---|
Assertion | rehalfcl | |- ( A e. RR -> ( A / 2 ) e. RR ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 2re | |- 2 e. RR |
|
2 | 2ne0 | |- 2 =/= 0 |
|
3 | redivcl | |- ( ( A e. RR /\ 2 e. RR /\ 2 =/= 0 ) -> ( A / 2 ) e. RR ) |
|
4 | 1 2 3 | mp3an23 | |- ( A e. RR -> ( A / 2 ) e. RR ) |