Hybrid subconvexity for class group 𝐿-functions and uniform sup norm bounds of Eisenstein series

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Asbjørn Christian Nordentoft

AbstractIn this paper, we study hybrid subconvexity bounds for class group 𝐿-functions associated to quadratic extensions K/\mathbb{Q} (real or imaginary). Our proof relies on relating the class group 𝐿-functions to Eisenstein series evaluated at Heegner points using formulas due to Hecke. The main technical contribution is the uniform sup norm bound for Eisenstein series E(z,1/2+it)\ll_{\varepsilon}y^{1/2}(\lvert t\rvert+1)^{1/3+\varepsilon}, y\gg 1, extending work of Blomer and Titchmarsh. Finally, we propose a uniform version of the sup norm conjecture for Eisenstein series.

2008 ◽  
Vol 189 ◽  
pp. 139-154 ◽  
Author(s):  
Shuji Yamamoto

AbstractLet K/F be a quadratic extension of number fields. After developing a theory of the Eisenstein series over F, we prove a formula which expresses a partial zeta function of K as a certain integral of the Eisenstein series. As an application, we obtain a limit formula of Kronecker’s type which relates the 0-th Laurent coefficients at s = 1 of zeta functions of K and F.


2019 ◽  
Vol 38 (4) ◽  
pp. 127-135 ◽  
Author(s):  
Abdelmalek Azizi ◽  
Abdelkader Zekhnini ◽  
Mohammed Taous

We study the capitulation of the 2-ideal classes of the field k =Q(\sqrt{p_1p_2q}, \sqrt{-1}), where p_1\equiv p_2\equiv-q\equiv1 \pmod 4  are different primes, in its three quadratic extensions contained in its absolute genus field k^{*} whenever the 2-class group of $\kk$ is of type $(2, 2, 2)$.


2018 ◽  
Vol 19 (2) ◽  
pp. 581-596 ◽  
Author(s):  
Valentin Blomer

Subconvexity bounds on the critical line are proved for general Epstein zeta-functions of $k$-ary quadratic forms. This is related to sup-norm bounds for unitary Eisenstein series on $\text{GL}(k)$ associated with the maximal parabolic of type $(k-1,1)$, and the exact sup-norm exponent is determined to be $(k-2)/8$ for $k\geqslant 4$. In particular, if $k$ is odd, this exponent is not in $\frac{1}{4}\mathbb{Z}$, which is relevant in the context of Sarnak’s purity conjecture and shows that it can in general not directly be generalized to Eisenstein series.


2011 ◽  
Vol 23 (6) ◽  
Author(s):  
Nicolas Templier

Author(s):  
Benson Farb ◽  
Dan Margalit

This chapter considers the Dehn–Lickorish theorem, which states that when g is greater than or equal to 0, the mapping class group Mod(Sɡ) is generated by finitely many Dehn twists about nonseparating simple closed curves. The theorem is proved by induction on genus, and the Birman exact sequence is introduced as the key step for the induction. The key to the inductive step is to prove that the complex of curves C(Sɡ) is connected when g is greater than or equal to 2. The simplicial complex C(Sɡ) is a useful combinatorial object that encodes intersection patterns of simple closed curves in Sɡ. More detailed structure of C(Sɡ) is then used to find various explicit generating sets for Mod(Sɡ), including those due to Lickorish and to Humphries.


Author(s):  
Benson Farb ◽  
Dan Margalit

The study of the mapping class group Mod(S) is a classical topic that is experiencing a renaissance. It lies at the juncture of geometry, topology, and group theory. This book explains as many important theorems, examples, and techniques as possible, quickly and directly, while at the same time giving full details and keeping the text nearly self-contained. The book is suitable for graduate students. It begins by explaining the main group-theoretical properties of Mod(S), from finite generation by Dehn twists and low-dimensional homology to the Dehn–Nielsen–Baer–theorem. Along the way, central objects and tools are introduced, such as the Birman exact sequence, the complex of curves, the braid group, the symplectic representation, and the Torelli group. The book then introduces Teichmüller space and its geometry, and uses the action of Mod(S) on it to prove the Nielsen-Thurston classification of surface homeomorphisms. Topics include the topology of the moduli space of Riemann surfaces, the connection with surface bundles, pseudo-Anosov theory, and Thurston's approach to the classification.


The contemporary era raises a series of red flags about electoral integrity in America. Problems include plummeting public trust, exacerbated by President Trump’s claims of massive electoral fraud. Confidence in the impartiality and reliability of information from the news media has eroded. And Russian meddling has astutely exploited both these vulnerabilities, heightening fears that the 2016 contest was unfair. This book brings together a first-class group of expert academics and practitioners to analyze challenges facing contemporary elections in America. Contributors analyze evidence for a series of contemporary challenges facing American elections, including the weaknesses of electoral laws, overly restrictive electoral registers, gerrymandering district boundaries, fake news, the lack of transparency, and the hodgepodge of inconsistent state regulations. The conclusion sets these issues in comparative context and draws out the broader policy lessons for improving electoral integrity and strengthening democracy.


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