Eisenstein-Kronecker classes, integrality of critical values of Hecke $L$-functions and $p$-adic interpolation
Guido Kings, Johannes Sprang
TL;DR
The paper develops a geometric framework for critical values of Hecke $L$-functions over arbitrary totally complex fields by constructing equivariant coherent Eisenstein-Kronecker classes on CM abelian schemes using the completed Poincaré bundle. It then provides explicit computations of these classes in terms of generalized Eisenstein-Kronecker series and currents, connecting them to the de Rham polylogarithm and CM-type decompositions. The results yield integrality statements for regularized values $L(\chi,0)$ after division by explicit periods, and enable a $p$-adic interpolation measure in the ordinary case, generalizing prior CM-field constructions (Damerell, Shimura, Katz) to the broader CM setting. The work also introduces refined classes to manage integrality and develops a robust link between CM types, periods, and special $L$-values, with potential implications for Deligne-type conjectures and CM motives of rank one.
Abstract
We show that for an arbitrary totally complex number field $L$ the (regularized) critical $L$-values of algebraic Hecke characters of $L$ divided by certain periods are algebraic integers. This relies on a new construction of an equivariant coherent cohomology class with values in the completion of the Poincaré bundle on an abelian scheme $\cal{A}$. From this we obtain a cohomology class for the automorphism group of a CM abelian scheme $\cal{A}$ with values in some canonical bundles, which can be explicitly calculated in terms of Eisenstein-Kronecker series. As a further consequence, using an infinitesimal trivialization of the Poincaré bundle, we construct a $p$-adic measure interpolating the critical $L$-values in the ordinary case. This generalizes previous results for CM fields by Damerell, Shimura and Katz and settles the algebraicity and $p$-adic interpolation in the remaining open cases of critical values of Hecke $L$-functions.
