activity
20122026
most citedA Gross--Kohnen--Zagier Type Theorem for Higher-Codimensional Heegner Cycles

15 citations · 104 across the 38 of their papers we have counts for

collaborators
Showing math.NTShow all

16 papers · 1 filter

math.NT2024

Modularity of special 0-cycles on toroidal compactifications of Shimura Varieties

Jan Hendrik Bruinier, Eugenia Rosu, Shaul Zemel

We consider the generating series of appropriately completed 0-dimensional special cycles on a toroidal compactification of an orthogonal or unitary Shimura variety with values in…

math.NT2023

Hermitian Jacobi Forms Having Modules as their Index and Vector-Valued Jacobi Forms

Shaul Zemel

We develop the theory of Hermitian Jacobi forms of lattice index, for both definite and indefinite Hermitian lattices. We also prove a theta decomposition theorem for vector-valued…

math.NT2021

Integral Bases and Invariant Vectors for Weil Representations

Shaul Zemel

We show that the Weil representation associated with any discriminant form admits a basis in which the action of the representation involves algebraic integers. The action of a gen…

math.NT2020

Shintani Lifts of Nearly Holomorphic Modular Forms

Yingkun Li, Shaul Zemel

In this paper, we compute the Fourier expansion of the Shintani lift of nearly holomorphic modular forms. As an application, we deduce modularity properties of generating series of…

math.NT2020

Seesaw Identities and Theta Contractions with Generalized Theta Functions, and Restrictions of Theta Lifts

Shaul Zemel

We prove a seesaw identity for theta functions with polynomials, and establish a formula for the corresponding theta contractions. We then use it to determine the restrictions of t…

math.NT2020★ 1 cited

Jacobi Forms of Indefinite Lattice Index

Shaul Zemel

We define Jacobi forms of indefinite lattice index, and show that they are isomorphic to vector-valued modular forms also in this setting. We also consider several operations of th…

math.NT2019

Special Cycles on Toroidal Compactifications of Orthogonal Shimura Varieties

Jan Hendrik Bruinier, Shaul Zemel

We determine the behavior of automorphic Green functions along the boundary components of toroidal compactifications of orthogonal Shimura varieties. We use this analysis to define…

math.NT2017

The Origin of the Beauregard--Suryanarayan Product on Pythagorean Triples

Shaul Zemel

We show how the multiplicative structure on Pythagorean triples defined by Beauregard--Suryanarayan arises from automorphisms of the hyperbolic plane, and how the structure theorem…

math.NT2016★ 3 cited

Shimura's Vector-Valued Modular Forms, Weight Changing Operators, and Laplacians

Shaul Zemel

We investigate the various types of weight raising and weight lowering operators on quasi-modular forms, or equivalently on Shimura's vector-valued modular forms involving symmetri…

math.NT2015★ 6 cited

Normalizers of Congruence Groups in and Automorphisms of Lattices

Shaul Zemel

We determine the normalizer in of several families of congruence subgroups of . In addition, we show how these tools can be used to evaluat…

math.NT2015★ 7 cited

Shimura Lifts of Weakly Holomorphic Modular Forms

Yingkun Li, Shaul Zemel

We show how to realize the Shimura lift of arbitrary level and character using the vector-valued theta lifts of Borcherds. Using the regularization of Borcherds' lift we extend the…

math.NT2015★ 9 cited

Regularized Pairings of Meromorphic Modular Forms and Theta Lifts

Shaul Zemel

We show that the meromorphic modular forms recently considered by Bringmann and Kane can be obtained as images of regularized theta lifts of Poincaré series under weight raising op…

math.NT2014★ 5 cited

Weight Changing Operators for Automorphic Forms on Grassmannians and Differential Properties of Certain Theta Lifts

Shaul Zemel

We define weight changing operators for automorphic forms on Grassmannians, i.e., on orthogonal groups, and investigate their basic properties. We then evaluate their action on the…

math.NT2013★ 8 cited

On Quasi-Modular Forms, Almost Holomorphic Modular Forms, and the Vector-Valued Modular Forms of Shimura

Shaul Zemel

We extend the relation between quasi-modular forms and modular forms to a wider class of functions. We then relate both forms to vector-valued modular forms with symmetric power re…

math.NT2013★ 15 cited

A Gross--Kohnen--Zagier Type Theorem for Higher-Codimensional Heegner Cycles

Shaul Zemel

We prove that Heegner cycles of codimension m+1 inside Kuga-Sato type varieties of dimension 2m+1 are coefficients of modular forms of weight 3/2+m in the appropriate quotient grou…

math.NT2012★ 14 cited

A -adic Approach to the Weil Representation of Discriminant Forms Arising from Even Lattices

Shaul Zemel

Suppose that is an even lattice with dual and level . Then the group , which is the unique non-trivial double cover of , admi…