Lemma 8.2.
Assuming that:
R
an integral domain which is
complete
with respect to an ideal
I
a
1
,
…
,
a
6
∈
R
K
=
Frac
(
R
)
Then
Ê
Ê
(
I
)
:
=
{
(
t
,
w
)
∈
E
(
K
)
|
t
,
w
∈
I
}
is a subgroup of
E
(
K
)
.