## Algebraic Cycles, L-Values, and Euler Systems

**Date:**
17 January - 26 May 2023

**Location: ** MSRI

**Event type:**
Extended Format

**Organisers: ** Henri Darmon (McGill), Ellen Eischen (Oregon), Benjamin Howard (BC), David Loeffler (Warwick), Christopher Skinner (Princeton), Sarah Zerbes (UCL), Wei Zhang (MIT)

**Website:**www.msri.org/programs/332

The fundamental conjecture of Birch and Swinnerton-Dyer relating the Mordell–Weil ranks of elliptic curves to their L-functions is one of the most important and motivating problems in number theory. It resides at the heart of a collection of important conjectures (due especially to Deligne, Beilinson, Bloch and Kato) that connect values of L-functions and their leading terms to cycles and Galois cohomology groups.

The study of special algebraic cycles on Shimura varieties has led to progress in our understanding of these conjectures. The arithmetic intersection numbers and the p-adic regulators of special cycles are directly related to the values and derivatives of L-functions, as shown in the pioneering theorem of Gross-Zagier and its p-adic avatars for Heegner points on modular curves. The cohomology classes of special cycles (and related constructions such as Eisenstein classes) form the foundation of the theory of Euler systems, providing one of the most powerful methods known to prove vanishing or finiteness results for Selmer groups of Galois representations.

The goal of this semester is to bring together researchers working on different aspects of this young but fast-developing subject, and to make progress on understanding the mysterious relations between L-functions, Euler systems, and algebraic cycles.

Professor Henri Darmon (McGill) has been appointed as a Clay Senior Scholar to participate in this program.

CMI Enhancement and Partnership Program