Theorem epr

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

	Ref	Expression
Assertion	epr	$$⊢\mathrm{e}\in {ℝ}^{+}$$

Proof

Step	Hyp	Ref	Expression
1		ere	$$⊢\mathrm{e}\in ℝ$$
2		epos	$$⊢0<\mathrm{e}$$
3	1 2	elrpii	$$⊢\mathrm{e}\in {ℝ}^{+}$$