Description: A number is nonzero iff its complex conjugate is nonzero. (Contributed by Mario Carneiro, 29-May-2016)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | recld.1 | |- ( ph -> A e. CC ) | |
| cjne0d.2 | |- ( ph -> A =/= 0 ) | ||
| Assertion | cjne0d | |- ( ph -> ( * ` A ) =/= 0 ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | recld.1 | |- ( ph -> A e. CC ) | |
| 2 | cjne0d.2 | |- ( ph -> A =/= 0 ) | |
| 3 | cjne0 | |- ( A e. CC -> ( A =/= 0 <-> ( * ` A ) =/= 0 ) ) | |
| 4 | 1 3 | syl | |- ( ph -> ( A =/= 0 <-> ( * ` A ) =/= 0 ) ) | 
| 5 | 2 4 | mpbid | |- ( ph -> ( * ` A ) =/= 0 ) |