Description: Zero is not a positive real. Axiom 9 of Apostol p. 20. (Contributed by NM, 27-Oct-2007)
Ref | Expression | ||
---|---|---|---|
Assertion | 0nrp | ⊢ ¬ 0 ∈ ℝ+ |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 0re | ⊢ 0 ∈ ℝ | |
2 | 1 | ltnri | ⊢ ¬ 0 < 0 |
3 | rpgt0 | ⊢ ( 0 ∈ ℝ+ → 0 < 0 ) | |
4 | 2 3 | mto | ⊢ ¬ 0 ∈ ℝ+ |