This is an inofficial mirror of http://metamath.tirix.org for personal testing of a visualizer extension only.

Metamath Proof Explorer

Theorem epr

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

		Ref	Expression
	Assertion	epr	⊢ e ∈ ℝ⁺

Step	Hyp	Ref	Expression
1		ere	⊢ e ∈ ℝ
2		epos	⊢ 0 < e
3	1 2	elrpii	⊢ e ∈ ℝ⁺