Number Theory

The influence of the Galois group structure on the Chebyshev bias in number fields

Speaker: 
Mounir Hayani
Date: 
Tue, Jun 18, 2024
Location: 
PIMS, University of British Columbia
Conference: 
Comparative Prime Number Theory
Abstract: 

In 2020, Fiorilli and Jouve proved an unconditional Chebyshev bias result for a Galois extension of number fields under a group theoretic condition on its Galois group. We extend their result to a larger family of groups. This leads us to characterize abelian groups enabling extreme biases. In the case of prime power degree extensions, we give a simple criterion implying extreme biases and we also investigate the corresponding Linnik-type question.

Class: 

The distribution of analytic ranks of elliptic curve over prime cyclic number fields

Speaker: 
Gyeongwon Oh
Date: 
Mon, Jun 17, 2024
Location: 
PIMS, University of British Columbia
Conference: 
Comparative Prime Number Theory
Abstract: 

Let $E$ be an elliptic curve over $\mathbb{Q}$ and $C_l$ be the family of prime cyclic extensions of degree $l$ over $\mathbb{Q}$. Under GRH for elliptic L-functions, we give a lower bound for the probability for $K \in C_l$ such that the difference $r_K(E) − r_\mathbb{Q}(E)$ between analytic rank is less than a for $a \asymp l$. This result gives conjectural evidence that the Diophantine Stability problem suggested by Mazur and Rubin holds for most of $K \in C_l$.

Class: 

Joint distribution of central values and orders of Sha groups of quadratic twists of an elliptic curve

Speaker: 
Peng-Jie Wong
Date: 
Mon, Jun 17, 2024
Location: 
PIMS, University of British Columbia
Conference: 
Comparative Prime Number Theory
Abstract: 

As a refinement of Goldfeld’s conjecture, there is a conjecture of Keating–Snaith asserting that $\log L(1/2,E_d)$ for certain quadratic twists $E_d$ of an elliptic curve $E$ behaves like a normal random variable. In light of this, Radziwill and Soundararajan conjectured that the distribution of $\log(|Sha(E_d)|/\sqrt{|d|}$ is approximately Gaussian for these $E_d$, and proved that the conjectures of Keating–Snaith and theirs are both valid “from above”. More recently, under GRH, they further established a lower bound for the involving distribution towards Keating–Snaith’s conjecture. In this talk, we shall discuss the joint distribution of central values and orders of Sha groups of $E_d$ and how to adapt Radziwill–Soundararajan’s methods to study upper bound and lower bounds for such a joint distribution if time allows.

Class: 

The Shanks–Rényi prime number race problem

Speaker: 
Youness Lamzouri
Date: 
Mon, Jun 17, 2024
Location: 
PIMS, University of British Columbia
Conference: 
Comparative Prime Number Theory
Abstract: 

Let $\pi(x; q, a)$ be the number of primes $p\leq x$ such that $p \equiv a (\mod q)$. The classical Shanks–Rényi prime number race problem asks, given positive integers $q \geq 3$ and $2 \leq r \leq \phi(q)$ and distinct reduced residue classes $a_1, a_2, . . . , a_r$ modulo $q$, whether there are infinitely many integers $n$ such that $\pi (n; q, a1) > \pi(n; q, a2) > \cdots > \pi(n; q, ar)$. In this talk, I will describe what is known on this problem when the number of competitors $r \geq 3$, and how this compares to the Chebyshev’s bias case which corresponds to $r = 2$.

Class: 

Fake mu's: Make Abstracts Great Again!

Speaker: 
Tim Trudgian
Date: 
Mon, Jun 17, 2024
Location: 
PIMS, University of British Columbia
Conference: 
Comparative Prime Number Theory
Abstract: 

The partial sums of the Liouville function $\lambda(n)$ are "often" negative, and yet the partials sums of the Möbius function $\mu(n)$ are positive or negative "roughly equally". How can this, be, given that $\mu(n)$ and $\lambda(n)$ are so similar? I shall discuss some problems in this area, some joint work with Greg Martin and Mike Mossinghoff, and a possible application to zeta-zeroes.

Class: 

Generic Representations and ABV packets for p-adic Groups

Speaker: 
Sarah Dijols
Date: 
Thu, Apr 18, 2024
Location: 
PIMS, University of British Columbia
Conference: 
UBC Number Theory Seminar
Abstract: 

After a brief introduction on the theory of p-adic groups complex representations, I will explain why tempered and generic Langlands parameters are open. I will further derive a number of consequences, in particular for the enhanced genericity conjecture of Shahidi and its analogue in terms of ABV packets. This is a joint work with Clifton Cunningham, Andrew Fiori, and Qing Zhang.

Class: 

Hypergeometric functions through the arithmetic kaleidoscope

Speaker: 
Ling Long
Date: 
Thu, Apr 11, 2024
Location: 
PIMS, University of British Columbia
Conference: 
UBC Number Theory Seminar
Abstract: 

The classical theory of hypergeometric functions, developed by generations of mathematicians including Gauss, Kummer, and Riemann, has been used substantially in the ensuing years within number theory, geometry, and the intersection thereof. In more recent decades, these classical ideas have been translated from the complex setting into the finite field and p
-adic settings as well.

In this talk, we will give a friendly introduction to hypergeometric functions, especially in the context of number theory.

Class: 

The Distribution of Logarithmic Derivatives of Quadratic L-functions in Positive Characteristic

Speaker: 
Félix Baril Boudreau
Date: 
Thu, Feb 29, 2024
Location: 
PIMS, University of Lethbridge
Zoom
Online
Conference: 
Lethbridge Number Theory and Combinatorics Seminar
Abstract: 

To each square-free monic polynomial $D$ in a fixed polynomial ring $\mathbb{F}_q[t]$, we can associate a real quadratic character $\chi_D$, and then a Dirichlet $L$-function $L(s,\chi_D)$. We compute the limiting distribution of the family of values $L'(1,\chi_D)/L(1,\chi_D)$ as $D$ runs through the square-free monic polynomials of $\mathbb{F}_q[t]$ and establish that this distribution has a smooth density function. Time permitting, we discuss connections of this result with Euler-Kronecker constants and ideal class groups of quadratic extensions. This is joint work with Amir Akbary.

Class: 

Bounds on the Number of Solutions to Thue Equations

Speaker: 
Greg Knapp
Date: 
Wed, Apr 10, 2024
Location: 
PIMS, University of Lethbridge
Online
Zoom
Conference: 
Analytic Aspects of L-functions and Applications to Number Theory
Abstract: 

In 1909, Thue proved that when $F(x,y)$ is an irreducible, homogeneous, polynomial with integer coefficients and degree at least 3, the inequality $\left\| F(x,y) \right\| \leq h$ has finitely many integer-pair solutions for any positive $h$.  Because of this result, the inequality $\left\| F(x,y) \right\| \leq h$  is known as Thue’s Inequality.  Much work has been done to find sharp bounds on the size and number of integer-pair solutions to Thue’s Inequality, with Mueller and Schmidt initiating the modern approach to this problem in the 1980s.  In this talk, I will describe different techniques used by Akhtari and Bengoechea; Baker; Mueller and Schmidt; Saradha and Sharma; and Thomas to make progress on this general problem.  After that, I will discuss some improvements that can be made to a counting technique used in association with “the gap principle” and how those improvements lead to better bounds on the number of solutions to Thue’s Inequality.

Class: 

Pro-p Iwahori Invariants

Speaker: 
Emanuele Bodon
Date: 
Thu, Mar 21, 2024
Location: 
PIMS, University of British Columbia
Online
Conference: 
UBC Number Theory Seminar
Abstract: 

Let $F$ be the field of $p$-adic numbers (or, more generally, a non-
archimedean local field) and let $G$ be $\mathrm{GL}_n(F)$ (or, more generally,
the group of $F$-points of a split connected reductive group). In the
framework of the local Langlands program, one is interested in studying
certain classes of representations of $G$ (and hopefully in trying to match
them with certain classes of representations of local Galois groups).

In this talk, we are going to focus on the category of smooth representations
of $G$ over a field $k$. An important tool to investigate this category is
given by the functor that, to each smooth representation $V$, attaches its
subspace of invariant vectors $V^I$ with respect to a fixed compact open
subgroup $I$ of $G$. The output of this functor is actually not just a $k$-
vector space, but a module over a certain Hecke algebra. The question we are
going to attempt to answer is: how much information does this functor preserve
or, in other words, how far is it from being an equivalence of categories? We
are going to focus, in particular, on the case that the characteristic of $k$
is equal to the residue characteristic of $F$ and $I$ is a specific subgroup
called "pro-$p$ Iwahori subgroup".

Class: 

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