Theorem epr

Description: Euler's constant _e is a positive real. (Contributed by Jeff Hankins, 22-Nov-2008)

	Ref	Expression
Assertion	epr	|- _e e. RR+

Proof

Step	Hyp	Ref	Expression
1		ere	|- _e e. RR
2		epos	|- 0 < _e
3	1 2	elrpii	|- _e e. RR+