Theorem mnfnepnf

Description: Minus and plus infinity are different. (Contributed by David A. Wheeler, 8-Dec-2018)

	Ref	Expression
Assertion	mnfnepnf	$$⊢\mathrm{-\infty }\ne \mathrm{+\infty }$$

Proof

Step	Hyp	Ref	Expression
1		pnfnemnf	$$⊢\mathrm{+\infty }\ne \mathrm{-\infty }$$
2	1	necomi	$$⊢\mathrm{-\infty }\ne \mathrm{+\infty }$$