Description:
Abstract
Let
$$\ell $$
ℓ
be an odd prime and d a positive integer. We determine when there exists a degree-d number field K and an elliptic curve E / K with
$$j(E)\in \mathbb {Q}\setminus \{0,1728\}$$
j
(
E
)
∈
Q
\
{
0
,
1728
}
for which
$$E(K)_\mathrm {tors}$$
E
(
K
)
tors
contains a point of order
$$\ell $$
ℓ
, conditionally on a conjecture of Sutherland. We likewise determine when there exists such a pair (K, E) for which the image of the associated mod-
$$\ell $$
ℓ
Galois representation is contained in a Cartan subgroup or its normalizer. We do the same under the stronger assumption that E is defined over
$$\mathbb {Q}$$
Q
.