Metamath Proof Explorer

Theorem negcld

Description: Closure law for negative. (Contributed by Mario Carneiro, 27-May-2016)

Ref Expression
Hypothesis negidd.1 
|- ( ph -> A e. CC )
Assertion negcld 
|- ( ph -> -u A e. CC )

Proof

Step Hyp Ref Expression
1 negidd.1 
 |-  ( ph -> A e. CC )
2 negcl 
 |-  ( A e. CC -> -u A e. CC )
3 1 2 syl 
 |-  ( ph -> -u A e. CC )