On non-trivial $Λ$-submodules with finite index of the plus/minus Selmer group over anticyclotomic $\mathbb{Z}_{p}$-extension at inert primes
Ryota Shii
TL;DR
This work studies plus/minus $p$-primary Selmer groups over the inert anticyclotomic $\mathbb{Z}_p$-extension of an imaginary quadratic field, proving that under mild hypotheses the dual Selmer group has no non-trivial $\Lambda$-submodules of finite index when it is $\Lambda$-cotorsion. It leverages Rubin's plus/minus Lubin–Tate formal-group framework (as established by BKO21) and a control theorem to transfer local conditions to the global Selmer module, extending Greenberg–Kim-type results from the cyclotomic/cyclotomic-ordinary setting to the inert anticyclotomic case. The approach yields corank and surjectivity statements via Poitou–Tate duality and a twisting technique, and provides concrete CM and non-CM examples through recent works of Agboola–Howard and Burungale–Kobayashi–Lei. The results have implications for the $p$-part of BSD and deepen understanding of $\Lambda$-adic invariants in non-abelian Iwasawa theory in the inert setting.
Abstract
Let $K$ be an imaginary quadratic field where $p$ is inert. Let $E$ be an elliptic curve defined over $K$ and suppose that $E$ has good supersingular reduction at $p$. In this paper, we prove that the plus/minus Selmer group of $E$ over the anticyclotomic $\mathbb{Z}_{p}$-extension of $K$ has no non-trivial $Λ$-submodules of finite index under mild assumptions for $E$. This is an analogous result to R. Greenberg and B. D. Kim for the anticyclotomic $\mathbb{Z}_{p}$-extension essentially. By applying the results of A. Agboola--B. Howard or A. Burungale--K. Büyükboduk--A. Lei, we can also construct examples satisfying the assumptions of our theorem.
