Theorem mnfnepnf

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

	Ref	Expression
Assertion	mnfnepnf	|- -oo =/= +oo

Proof

Step	Hyp	Ref	Expression
1		pnfnemnf	|- +oo =/= -oo
2	1	necomi	|- -oo =/= +oo