Theorem 16.1.
Assuming that:
f
∈
K
(
E
′
)
and
g
∈
K
(
E
)
div
(
f
)
=
n
(
T
)
−
n
(
0
)
ϕ
∗
f
=
g
n
Then
α
(
P
)
=
f
(
P
)
(
m
o
d
(
K
∗
)
n
)
for all
P
∈
E
;
(
K
)
∖
{
0
,
T
}
.