Modular Invariant of Quantum Tori

Toric modular forms and nonvanishing of L-functions

In a previous paper \cite{BorGunn}, we defined the space of toric forms $\TTT(l)$, and showed that it is a finitely generated subring of the holomorphic modular forms of integral weight on the congruence group $Γ_1(l)$. In this article we prove the following theorem: modulo Eisenstein series, the weight two toric forms coincide exactly with the vector space generated by all cusp eigenforms f such that $L(f,1) \not = 0$. The proof uses work of Merel, and involves an explicit computation of the intersection pairing on Manin symbols.

Toric varieties and modular forms

Let $N\subset \RR^{r}$ be a lattice, and let $°\colon N \to \CC$ be a piecewise-linear function that is linear on the cones of a complete rational polyhedral fan. Under certain conditions on $°$, the data $(N,°)$ determines a function $f\colon {\HHH}\to \CC$ that is a holomorphic modular form of weight $r$ for the congruence subgroup $Γ_{1} (l) $. Moreover, by considering all possible pairs $(N ,°)$, we obtain a natural subring ${\TTT} (l)$ of modular forms with respect to $Γ_{1} (l) $. We construct an explicit set of generators for $\TTT (l)$, and show that ${\TTT} (l)$ is stable under the ac…

Modular Invariant of Quantum Tori II: The Golden Mean

In our first article in this series ("Modular Invariant of Quantum Tori I: Definitions Nonstandard and Standard" arXiv:0909.0143) a modular invariant of quantum tori was defined. In this paper, we consider the case of the quantum torus associated to the golden mean. We show that the modular invariant is approximately 9538.249655644 by producing an explicit formula for it involving weighted versions of the Rogers-Ramanujan functions.

代数环面的4次上同调不变量

Degree 4 cohomological invariants of algebraic tori

本文通过确定代数环面分类主齐性空间的 motive，给出了描述其4次上同调不变量的正合序列，并利用已知结果导出了4次非分歧上同调群的公式。

Geometric Continued Fractions as Invariants in the Topological Classification of Anosov Diffeomorphisms of Tori

We show how an object from the combinatorially geometric version of the analytical number theory, namely geometric continued fractions, appears in the classical smooth dynamics, namely in the problem on the topological classification of Anosov diffeomorphisms of tori.