Description: -u _i is a complex number. (Contributed by David A. Wheeler, 7-Dec-2018)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | negicn | |- -u _i e. CC | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | ax-icn | |- _i e. CC | |
| 2 | negcl | |- ( _i e. CC -> -u _i e. CC ) | |
| 3 | 1 2 | ax-mp | |- -u _i e. CC |