Arithmetic statistics for Galois deformation rings
Given an elliptic curve E defined over the rational numbers and a prime p at which E has good reduction, we consider the Galois deformation ring parametrizing lifts of the residual representation on the p -torsion group E [ p ]. The deformations considered are subject to the flat condition at p . Fo...
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| Vydáno v: | The Ramanujan journal Ročník 64; číslo 3; s. 685 - 708 |
|---|---|
| Hlavní autoři: | , |
| Médium: | Journal Article |
| Jazyk: | angličtina |
| Vydáno: |
New York
Springer US
01.07.2024
|
| Témata: | |
| ISSN: | 1382-4090, 1572-9303 |
| On-line přístup: | Získat plný text |
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| Shrnutí: | Given an elliptic curve
E
defined over the rational numbers and a prime
p
at which
E
has good reduction, we consider the Galois deformation ring parametrizing lifts of the residual representation on the
p
-torsion group
E
[
p
]. The deformations considered are subject to the flat condition at
p
. For a fixed elliptic curve without complex multiplication, it is shown that these deformation rings are unobstructed for all but finitely many primes. For a fixed prime
p
and varying elliptic curve
E
, we relate the problem to the question of how often
p
does not divide the modular degree. Heuristics due to M.Watkins based on those of Cohen and Lenstra indicate that this proportion should be
∏
i
≥
1
1
-
1
p
i
≈
1
-
1
p
-
1
p
2
. This heuristic is supported by computations which indicate that most elliptic curves (satisfying further conditions) have smooth deformation rings at a given prime
p
≥
5
, and this proportion comes close to
100
%
as
p
gets larger. |
|---|---|
| ISSN: | 1382-4090 1572-9303 |
| DOI: | 10.1007/s11139-024-00839-0 |