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Database
ELEMENTARY NUMBER THEORY
Elementary prime number theory
Lagrange's four-square theorem
df-gz
Metamath Proof Explorer
Definition df-gz
Description: Define the set of gaussian integers, which are complex numbers whose real
and imaginary parts are integers. (Note that the [ _i ] is actually
part of the symbol token and has no independent meaning.) (Contributed by Mario Carneiro , 14-Jul-2014)
Ref
Expression
Assertion
df-gz
⊢ ℤ i = x ∈ ℂ | ℜ ⁡ x ∈ ℤ ∧ ℑ ⁡ x ∈ ℤ
Detailed syntax breakdown
Step
Hyp
Ref
Expression
0
cgz
class ℤ i
1
vx
setvar x
2
cc
class ℂ
3
cre
class ℜ
4
1
cv
setvar x
5
4 3
cfv
class ℜ ⁡ x
6
cz
class ℤ
7
5 6
wcel
wff ℜ ⁡ x ∈ ℤ
8
cim
class ℑ
9
4 8
cfv
class ℑ ⁡ x
10
9 6
wcel
wff ℑ ⁡ x ∈ ℤ
11
7 10
wa
wff ℜ ⁡ x ∈ ℤ ∧ ℑ ⁡ x ∈ ℤ
12
11 1 2
crab
class x ∈ ℂ | ℜ ⁡ x ∈ ℤ ∧ ℑ ⁡ x ∈ ℤ
13
0 12
wceq
wff ℤ i = x ∈ ℂ | ℜ ⁡ x ∈ ℤ ∧ ℑ ⁡ x ∈ ℤ