270 research outputs found
Modular forms and elliptic curves over the cubic field of discriminant -23
Let F be the cubic field of discriminant -23 and let O be its ring of
integers. By explicitly computing cohomology of congruence subgroups of
GL(2,O), we computationally investigate modularity of elliptic curves over F.Comment: Incorporated referee's comment
Perfect forms over totally real number fields
A rational positive-definite quadratic form is perfect if it can be
reconstructed from the knowledge of its minimal nonzero value m and the finite
set of integral vectors v such that f(v) = m. This concept was introduced by
Voronoi and later generalized by Koecher to arbitrary number fields. One knows
that up to a natural "change of variables'' equivalence, there are only
finitely many perfect forms, and given an initial perfect form one knows how to
explicitly compute all perfect forms up to equivalence. In this paper we
investigate perfect forms over totally real number fields. Our main result
explains how to find an initial perfect form for any such field. We also
compute the inequivalent binary perfect forms over real quadratic fields
Q(\sqrt{d}) with d \leq 66.Comment: 11 pages, 2 figures, 1 tabl
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