Metamath Proof Explorer


Theorem negne0i

Description: The negative of a nonzero number is nonzero. (Contributed by NM, 30-Jul-2004)

Ref Expression
Hypotheses negidi.1 A
negne0i.2 A 0
Assertion negne0i A 0

Proof

Step Hyp Ref Expression
1 negidi.1 A
2 negne0i.2 A 0
3 1 negne0bi A 0 A 0
4 2 3 mpbi A 0