Description: The negative of a nonzero number is nonzero. (Contributed by NM, 30-Jul-2004)
Ref | Expression | ||
---|---|---|---|
Hypotheses | negidi.1 | |
|
negne0i.2 | |
||
Assertion | negne0i | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | negidi.1 | |
|
2 | negne0i.2 | |
|
3 | 1 | negne0bi | |
4 | 2 3 | mpbi | |