Database
REAL AND COMPLEX NUMBERS
Order sets
Positive reals (as a subset of complex numbers)
0nrp
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ltsubrp
Metamath Proof Explorer
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Unicode
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
∈
ℝ
+
Proof
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
+