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We compute the divisor of the modular equation on the modular curve $\Gamma_0(N) \backslash \mathbb H^*$ and then find recurrence relations satisfied by the modular traces of the Hauptmodul for any congruence subgroup $\Gamma_0(N)$ of genus…

Number Theory · Mathematics 2020-02-07 Bumkyu Cho

We introduce an $L$-series associated to real-analytic modular forms which transform with weight $(r,s)\in\mathbb{Z}^2$ under $\Gamma_0(N)$. These $L$-series satisfy a functional equation and converse theorem. We also discuss examples of…

Number Theory · Mathematics 2023-12-19 Joshua Drewitt , Joshua Pimm

Evaluation of low degree hypergeometric polynomials to zero defines an algebraic hypersurface in the affine space of the free parameters and the argument. This article investigates the algebraic surfaces 2F1(-N,b;c;z)=0 for N=3 and N=4. As…

Algebraic Geometry · Mathematics 2025-03-26 Raimundas Vidunas

We introduce and study the moduli stack $\mathcal{Y}$ of Breuil-Kisin modules with $\hat{G}$-structure and descent data, or Breuil-Kisin $(\Gamma,\hat{G})$-torsors for short. Specifically, for a dominant cocharacter $\mu$, we define the…

Number Theory · Mathematics 2025-06-16 Eivind Otto Hjelle

Let X be a geometrically irreducible smooth projective curve over a field k. We describe the algebra of endomorphisms of indecomposable unstable vector bundles over X of rank 2 and degree d. Fixing some numerical invariants, namely the…

Algebraic Geometry · Mathematics 2011-03-01 L. Brambila-Paz , Osbaldo Mata , Nitin Nitsure

We compile a complete list of isomorphism class representatives of curves of genus 6 over $\mathbb{F}_2$. We use explicit descriptions of canonical curves in each stratum of the Brill--Noether stratification of the moduli space…

Algebraic Geometry · Mathematics 2024-02-02 Yongyuan Huang , Kiran S. Kedlaya , Jun Bo Lau

We classify all of the groups with twelve or fewer subgroups. This paper is the proof of the entries in a submission to the Online Encyclopedia of Integer Sequences.

Group Theory · Mathematics 2020-07-09 Michael C Slattery

Suppose that $\ell \geq 5$ is prime. For a positive integer $N$ with $4 \mid N$, previous works studied properties of half-integral weight modular forms on $\Gamma_0(N)$ which are supported on finitely many square classes modulo $\ell$, in…

Number Theory · Mathematics 2021-11-09 Robert Dicks

This research paper introduces two new constraint types and four subtypes of database constraints added to our (Elementary) Mathematical Data Model, which are the duals of the existence and non-existence ones. They are formally defined,…

Databases · Computer Science 2026-05-26 Christian Mancas

The finite symplectic group Sp(2g) over the field of two elements has a natural representation on the vector space of Siegel modular forms of given weight for the principal congruence subgroup of level two. In this paper we decompose this…

Algebraic Geometry · Mathematics 2008-05-05 Francesco Dalla Piazza , Bert van Geemen

There is an established bijection between finite-index subgroups Gamma of Gamma(2) and bipartite graphs on surfaces, or, equivalently, certain triples of permutations. We utilize this relationship to study both congruence and noncongruence…

Number Theory · Mathematics 2013-07-29 Erica J. Whitaker

We describe a systematic investigation into the existence of congruences between the mod $p$ torsion modules of elliptic curves defined over $\mathbb{Q}$, including methods to determine the symplectic type of such congruences. We classify…

Number Theory · Mathematics 2020-08-05 John Cremona , Nuno Freitas

We construct infinitely many abelian surfaces A defined over the rational numbers such that, for a prime ell <= 7, the ell-torsion subgroup of A is not isomorphic as a Galois module to the ell-torsion subgroup of its dual. We do this by…

Number Theory · Mathematics 2025-09-18 Sarah Frei , Katrina Honigs , John Voight

This article investigates structural, geometrical, and topological characterizations and properties of weakly modular graphs and of cell complexes derived from them. The unifying themes of our investigation are various `nonpositive…

Metric Geometry · Mathematics 2022-03-03 Jérémie Chalopin , Victor Chepoi , Hiroshi Hirai , Damian Osajda

Necessary and sufficient conditions are given for a $G$-graded simple module over a unital associative algebra, graded by an abelian group $G$, to be isomorphic to a loop module of a simple module, as well as for two such loop modules to be…

Representation Theory · Mathematics 2016-09-12 Alberto Elduque , Mikhail Kochetov

We generalize the work of Ohta on the congruence modules attached to elliptic Eisenstein series to the setting of Hilbert modular forms. Our work involves three parts. In the first part, we construct Eisenstein series adelically and compute…

Number Theory · Mathematics 2020-02-11 Sheng-Chi Shih

We give a computationally effective criterion for determining whether a finite-index subgroup of SL(2, Z) is a congruence subgroup, extending earlier work of Hsu for subgroups of PSL(2, Z).

Number Theory · Mathematics 2019-02-20 Thomas Hamilton , David Loeffler

We analyze Weierstrass cycles and tautological rings in moduli space of smooth algebraic curves and in moduli spaces of integral algebraic curves with embedded disks with special attention to moduli spaces of curves having genus $\leq 6$.…

Algebraic Geometry · Mathematics 2015-03-10 Jia-Ming Liou , Albert Schwarz , Renjun Xu

The notion of formal Siegel modular forms for an arithmetic subgroup $\Gamma$ of the symplectic group of genus $n$ is a generalization of symmetric formal Fourier-Jacobi series. Assuming an upper bound on the affine covering number of the…

Number Theory · Mathematics 2024-07-09 Jan Hendrik Bruinier , Martin Raum

We compute cohomology of the moduli space of genus three curves with level two structure and some related spaces. In particular, we determine the cohomology groups of the moduli space of plane quartics with level two structure as…

Algebraic Geometry · Mathematics 2020-08-03 Olof Bergvall