Database
REAL AND COMPLEX NUMBERS
Integer sets
Simple number properties
rehalfcl
Next ⟩
half0
Metamath Proof Explorer
Ascii
Unicode
Theorem
rehalfcl
Description:
Real closure of half.
(Contributed by
NM
, 1-Jan-2006)
Ref
Expression
Assertion
rehalfcl
⊢
A
∈
ℝ
→
A
2
∈
ℝ
Proof
Step
Hyp
Ref
Expression
1
2re
⊢
2
∈
ℝ
2
2ne0
⊢
2
≠
0
3
redivcl
⊢
A
∈
ℝ
∧
2
∈
ℝ
∧
2
≠
0
→
A
2
∈
ℝ
4
1
2
3
mp3an23
⊢
A
∈
ℝ
→
A
2
∈
ℝ