Metamath Proof Explorer


Theorem 0nrp

Description: Zero is not a positive real. Axiom 9 of Apostol p. 20. (Contributed by NM, 27-Oct-2007)

Ref Expression
Assertion 0nrp ¬ 0 +

Proof

Step Hyp Ref Expression
1 0re 0
2 1 ltnri ¬ 0 < 0
3 rpgt0 0 + 0 < 0
4 2 3 mto ¬ 0 +