**Description:** -u _i is a complex number. (Contributed by David A. Wheeler, 7-Dec-2018)

Ref | Expression | ||
---|---|---|---|

Assertion | negicn | $${\u22a2}-\mathrm{i}\in \u2102$$ |

Step | Hyp | Ref | Expression |
---|---|---|---|

1 | ax-icn | $${\u22a2}\mathrm{i}\in \u2102$$ | |

2 | negcl | $${\u22a2}\mathrm{i}\in \u2102\to -\mathrm{i}\in \u2102$$ | |

3 | 1 2 | ax-mp | $${\u22a2}-\mathrm{i}\in \u2102$$ |