Theorem icossxr

Description: A closed-below, open-above interval is a subset of the extended reals. (Contributed by FL, 29-May-2014) (Revised by Mario Carneiro, 4-Jul-2014)

	Ref	Expression
Assertion	icossxr	|- ( A [,) B ) C_ RR*

Proof

Step	Hyp	Ref	Expression
1		df-ico	|- [,) = ( x e. RR* , y e. RR* |-> { z e. RR* | ( x <_ z /\ z < y ) } )
2	1	ixxssxr	|- ( A [,) B ) C_ RR*