Description: Extended real version of negnegd . (Contributed by Glauco Siliprandi, 2-Jan-2022)
Ref | Expression | ||
---|---|---|---|
Hypothesis | xnegnegd.1 | |- ( ph -> A e. RR* ) |
|
Assertion | xnegnegd | |- ( ph -> -e -e A = A ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | xnegnegd.1 | |- ( ph -> A e. RR* ) |
|
2 | xnegneg | |- ( A e. RR* -> -e -e A = A ) |
|
3 | 1 2 | syl | |- ( ph -> -e -e A = A ) |