2019
DOI: 10.1112/jlms.12271
|View full text |Cite
|
Sign up to set email alerts
|

The average size of the 3‐isogeny Selmer groups of elliptic curves y2=x3+k

Abstract: The elliptic curve Ek:y2=x3+k admits a natural 3‐isogeny ϕk:Ek→E−27k. We compute the average size of the ϕk‐Selmer group as k varies over the integers. Unlike previous results of Bhargava and Shankar on n‐Selmer groups of elliptic curves, we show that this average can be very sensitive to congruence conditions on k; this sensitivity can be precisely controlled by the Tamagawa numbers of Ek and E−27k. As a consequence, we prove that the average rank of the curves Ek, k∈Z, is less than 1.21 and over 23% (respect… Show more

Help me understand this report
View preprint versions

Search citation statements

Order By: Relevance

Paper Sections

Select...
2
1
1

Citation Types

1
35
0

Year Published

2019
2019
2025
2025

Publication Types

Select...
7

Relationship

1
6

Authors

Journals

citations
Cited by 20 publications
(36 citation statements)
references
References 36 publications
1
35
0
Order By: Relevance
“…For any place p of F , we write F p for the p-adic completion of F . From the results of [1], one naturally expects that the average number of non-trivial elements of Sel φ (A s ) is governed by an Euler product whose factor at p is the average size of the local φ-Selmer ratio…”
Section: Resultsmentioning
confidence: 99%
See 1 more Smart Citation
“…For any place p of F , we write F p for the p-adic completion of F . From the results of [1], one naturally expects that the average number of non-trivial elements of Sel φ (A s ) is governed by an Euler product whose factor at p is the average size of the local φ-Selmer ratio…”
Section: Resultsmentioning
confidence: 99%
“…We also provide the first known examples of absolutely simple abelian varieties A over Q having dimension greater than one for which the average rank of A s (Q) is bounded, and indeed we give such examples over any number field F and in arbitrarily large dimension. 1 The proofs of these results are accomplished through a computation of the average size of a family of Selmer groups, namely, the φ-Selmer groups associated to a quadratic twist family of 3-isogenies φ s : A s → A ′ s of abelian varieties. There have been a number of recent results on the average sizes of Selmer groups in large universal families of elliptic curves or Jacobians of higher genus curves (see, e.g., [2,3,5,6,39,40,44]) obtained via geometry-of-numbers methods.…”
Section: Introductionmentioning
confidence: 99%
“…VIII, Exercise 8.1 with m = 2. In particular, c(E) is bounded by a multiple of the number of places of bad reduction of E plus the 2-rank of the class group of K = Q(E[2]) = Q(E (D) [2]).…”
Section: Since the Faltings Height Satisfiesmentioning
confidence: 99%
“…The proof of Theorem 1.6 combines Theorem 1.1 with results of Fouvry [12] on upper bounds for the average size of 3-isogeny Selmer groups for Mordell elliptic curves, which in turn relies on the Davenport-Heilbronn theorem on 3-torsion of class groups of quadratic fields. See [2] for the exact computation of the average size of the 3-isogeny Selmer groups of Mordell elliptic curves.…”
Section: Introductionmentioning
confidence: 99%
See 1 more Smart Citation