Let $p$ be an odd prime number and let $K$ be an imaginary quadratic field in which $p$ is split. Let $f$ be a modular form with good reduction at $p$. We study the variation of the Bloch--Kato Selmer groups and the Bloch--Kato--Shafarevich--Tate groups of $f$ over the anticyclotomic $mathbf{Z}_p$-extension $K_infty$ of $K$. In particular, we show that under the generalized Heegner hypothesis, if the $p$-localization of the generalized Heegner cycle attached to $f$ is primitive and certain local conditions hold, then the Pontryagin dual of the Selmer group of $f$ over $K_infty$ is free over the Iwasawa algebra. Consequently, the Bloch--Kato--Shafarevich--Tate groups of $f$ vanish. This generalizes earlier works of Matar and Matar--Nekov'av{r} on elliptic curves. Furthermore, our proof applies uniformly to the ordinary and non-ordinary settings.
{"title":"On the structure of the Bloch--Kato Selmer groups of modular forms over anticyclotomic $mathbf{Z}_p$-towers","authors":"Antonio Lei, Luca Mastella, Luochen Zhao","doi":"arxiv-2409.11966","DOIUrl":"https://doi.org/arxiv-2409.11966","url":null,"abstract":"Let $p$ be an odd prime number and let $K$ be an imaginary quadratic field in\u0000which $p$ is split. Let $f$ be a modular form with good reduction at $p$. We\u0000study the variation of the Bloch--Kato Selmer groups and the\u0000Bloch--Kato--Shafarevich--Tate groups of $f$ over the anticyclotomic\u0000$mathbf{Z}_p$-extension $K_infty$ of $K$. In particular, we show that under\u0000the generalized Heegner hypothesis, if the $p$-localization of the generalized\u0000Heegner cycle attached to $f$ is primitive and certain local conditions hold,\u0000then the Pontryagin dual of the Selmer group of $f$ over $K_infty$ is free\u0000over the Iwasawa algebra. Consequently, the Bloch--Kato--Shafarevich--Tate\u0000groups of $f$ vanish. This generalizes earlier works of Matar and\u0000Matar--Nekov'av{r} on elliptic curves. Furthermore, our proof applies\u0000uniformly to the ordinary and non-ordinary settings.","PeriodicalId":501064,"journal":{"name":"arXiv - MATH - Number Theory","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142259845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We establish a Galois-theoretic trichotomy governing Diophantine stability for genus $0$ curves. We use it to prove that the curve associated to the Hilbert symbol is Diophantine stable with probability $1$. Our asymptotic formula for the second order term exhibits strong bias towards instability.
{"title":"Diophantine stability and second order terms","authors":"Carlo Pagano, Efthymios Sofos","doi":"arxiv-2409.12144","DOIUrl":"https://doi.org/arxiv-2409.12144","url":null,"abstract":"We establish a Galois-theoretic trichotomy governing Diophantine stability\u0000for genus $0$ curves. We use it to prove that the curve associated to the\u0000Hilbert symbol is Diophantine stable with probability $1$. Our asymptotic\u0000formula for the second order term exhibits strong bias towards instability.","PeriodicalId":501064,"journal":{"name":"arXiv - MATH - Number Theory","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142259844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We show that the systems of Hecke eigenvalues that appear in the coherent cohomology with coefficients in automorphic line bundles of any mod $p$ abelian type compact Shimura variety at hyperspecial level are the same as those appearing in any Hecke-equivariant closed subscheme. We also prove analogous results for noncompact Shimura varieties or nonclosed subschemes, such as Ekedahl-Oort strata, length strata and central leaves.
{"title":"Systems of Hecke eigenvalues on subschemes of Shimura varieties","authors":"Stefan Reppen","doi":"arxiv-2409.11720","DOIUrl":"https://doi.org/arxiv-2409.11720","url":null,"abstract":"We show that the systems of Hecke eigenvalues that appear in the coherent\u0000cohomology with coefficients in automorphic line bundles of any mod $p$ abelian\u0000type compact Shimura variety at hyperspecial level are the same as those\u0000appearing in any Hecke-equivariant closed subscheme. We also prove analogous\u0000results for noncompact Shimura varieties or nonclosed subschemes, such as\u0000Ekedahl-Oort strata, length strata and central leaves.","PeriodicalId":501064,"journal":{"name":"arXiv - MATH - Number Theory","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142259847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Given a supersingular elliptic curve, the supersingular endomorphism ring problem is to compute all of its endomorphisms. We use the correspondence between maximal orders in quaternion algebra $B_{p,infty}$ and positive ternary quadratic forms with discriminant $p$ to solve the supersingular endomorphism ring problem. Let $c<3p/16$ be a prime or $c=1$. Let $E$ be a $mathbb{Z}[sqrt{-cp}]$-oriented supersingular elliptic curve defined over $mathbb{F}_{p^2}$. There exists a subgroup $G$ of order $c$, and $text{End}(E,G)$ is isomorphic to an Eichler order in $B_{p,infty}$ of level $c$. If the endomorphism ring $text{End}(E,G)$ is known, then we can compute $text{End}(E)$ by solving two square roots in $mathbb{F}_c$. In particular, let $D