Description: Closure of the natural logarithm function. (Contributed by NM, 21-Apr-2008) (Revised by Mario Carneiro, 23-Sep-2014)
Ref | Expression | ||
---|---|---|---|
Assertion | logcl | |- ( ( A e. CC /\ A =/= 0 ) -> ( log ` A ) e. CC ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | logrncl | |- ( ( A e. CC /\ A =/= 0 ) -> ( log ` A ) e. ran log ) |
|
2 | logrncn | |- ( ( log ` A ) e. ran log -> ( log ` A ) e. CC ) |
|
3 | 1 2 | syl | |- ( ( A e. CC /\ A =/= 0 ) -> ( log ` A ) e. CC ) |