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Database
BASIC REAL AND COMPLEX FUNCTIONS
Basic trigonometry
The natural logarithm on complex numbers
df-cxp
Metamath Proof Explorer
Description: Define the power function on complex numbers. Note that the value of
this function when x = 0 and ( Re y ) <_ 0 , y =/= 0 should
properly be undefined, but defining it by convention this way simplifies
the domain. (Contributed by Mario Carneiro , 2-Aug-2014)
Ref
Expression
Assertion
df-cxp
⊢ ↑ c = x ∈ ℂ , y ∈ ℂ ⟼ if x = 0 if y = 0 1 0 e y ⁢ log ⁡ x
Detailed syntax breakdown
Step
Hyp
Ref
Expression
0
ccxp
class ↑ c
1
vx
setvar x
2
cc
class ℂ
3
vy
setvar y
4
1
cv
setvar x
5
cc0
class 0
6
4 5
wceq
wff x = 0
7
3
cv
setvar y
8
7 5
wceq
wff y = 0
9
c1
class 1
10
8 9 5
cif
class if y = 0 1 0
11
ce
class exp
12
cmul
class ×
13
clog
class log
14
4 13
cfv
class log ⁡ x
15
7 14 12
co
class y ⁢ log ⁡ x
16
15 11
cfv
class e y ⁢ log ⁡ x
17
6 10 16
cif
class if x = 0 if y = 0 1 0 e y ⁢ log ⁡ x
18
1 3 2 2 17
cmpo
class x ∈ ℂ , y ∈ ℂ ⟼ if x = 0 if y = 0 1 0 e y ⁢ log ⁡ x
19
0 18
wceq
wff ↑ c = x ∈ ℂ , y ∈ ℂ ⟼ if x = 0 if y = 0 1 0 e y ⁢ log ⁡ x