This thesis explores arithmetic aspects of function fields, viewed as analogues of number fields. We begin by reviewing the classical theory: valuation rings, places, and divisors, concluding with the Riemann–Roch theorem and its consequences. We then study algebraic extensions of function fields, including Galois extensions, the Hurwitz genus formula, and constant field extensions, with an application to elliptic function fields. A second part develops the theory of characters, leading to applications of Gauss and Jacobi sums in solving Diophantine equations over finite fields. The main contribution is presented in the final chapter: a function field analogue of results on the divisor function and B-free integers. We introduce B-free polynomials and establish asymptotic estimates for averages of the divisor function, extending results of Camargo [dC24] to the function field setting.

The (logarithmic) Mahler measure of a non-zero rational function P in n variables is defined as the arithmetic mean of log |P| restricted to the standard n-torus (T^n = {(x_1, ..., x_n) ∈ (C*)^n: |x_i| = 1, for all 1 ≤ i ≤ n}) with respect to the unique Haar measure (normalized arc measure) on T^n. It has connections to heights, hyperbolic volumes, arithmetic dynamics, and special values of L-functions. Various generalizations of this definition exist in the literature. This thesis is dedicated to exploring two such generalizations: firstly, when the unit torus is substituted by a torus with arbitrary radii (T_{a_1, ..., a_n})^n = {(x_1, ..., x_n) ∈ (C*)^n: |x_i| = a_i, for all 1 ≤ i ≤ n} (referred to as the \textit{generalized Mahler measure}), and secondly, when the normalized arc measure on the unit torus is replaced by the normalized area measure on the unit disk (referred to as the \textit{areal Mahler measure}). Our primary objective is to quantify the behavior of the Mahler measure of P under such alterations. This thesis is structured into five projects. 1. In Chapter 1, we investigate the definition of the generalized Mahler measure for all Laurent polynomials in n-variables when they do not vanish on the integration torus. This work has been published in [106]. 2. In Chapter 2, we exhibit some nontrivial evaluations of the areal Mahler measure of multivariable polynomials, defined by Pritsker. This is a joint work with Lalin, and has been published in [84]. 3. In Chapter 3, we investigate how the areal Mahler measure changes with the power change of variables. This a joint work with Lalin, and has been published in [83]. 4. In Chapter 4, we investigate the Mahler measure of a particular family of rational functions with an arbitrary number of variables and an arbitrary degree in one of the variables. This is a joint work with Lalin and Nair, and will appear in [81]. 5. In Chapter 5, we evaluate the areal Mahler measure of a family of polynomials using the areal analogue of the Zeta Mahler measure. This is an ongoing joint work with Lalin, Nair, and Ringeling.

Polynomials are a fundamental entity in Mathematics, especially in Number Theory. Height functions are useful tools employed to study polynomials in a systematic way and in many cases greatly simplify the proof of complex theorems. \(L\)-functions form another class of mathematical objects that find great importance in Number Theory. The celebrated Riemann zeta function is one of the most well-known and foundational examples of an \(L\)-function. This dissertation revolves around the Mahler measure - a height function on polynomials that often appears as special values of \(L\)-functions and forms a mysterious link between these two areas of research. We aim to explore three questions concerning the Mahler measure of several polynomial families that are constructed via certain Möbius transformations. The first result, published in [Bull. Lond. Math. Soc. 55 (2023), 1129-1142], describes a family of non-trivial transformations which when applied on any polynomial, yields increasingly complex polynomials without changing its Mahler measure. This leads to several identities involving the Mahler measure of polynomials and resolves many conjectural relations. In the second result, we obtain explicit formulae for the Mahler measure of polynomial families that can have as many variables as desired. These Mahler measures are expressed in terms of \(\zeta\)-values and \(L\)-values corresponding to the primitive Dirichlet character of conductor 3. The result builds on the ideas of Lalín for constructing such \(n\)-variable families in a new direction, opening the doors to possibly many more interesting relations of the same kind. This result has been submitted for publication. Finally, our third result, accepted for publication, concerns the Mahler measure of yet another \(n\)-variable polynomial family which has non-linear degree, as opposed to the families in the work of Lalín and our second result in which each variable had linear degree. This result leads to the expression of the Mahler measure in terms of several length 2 polylogarithms which are reduced to length one polylogarithms using appropriate identities. We present certain examples where these expressions can be written in terms of zeta values and values of Dirichlet \(L\)-functions of characters with conductors 4, 8 and 12.

In mathematics, heights are functions used to measure the complexity of an object. When only a finite number of elements have a bounded height, we say that this height has the Northcott property. One of the advantages of this property is that the heights possessing it can be used to distinguish finite subsets of an infinite family of objects. Recently, Pazuki and Pengo [47] studied the Northcott property where the height considered was the evaluation of Dedekind zeta functions at an integer n. This thesis contains, first of all, an article describing a similar study on the evaluation of zeta functions of function fields. This first article pushes this reflection on a larger domain by considering the evaluation on any point s of the complex plane instead of integer values n. We show that for points belonging to a certain region {s ∈ C ∶ Re(s) < σ0} where 0 < σ0 < 1/2, the considered height has the Northcott property, while for those belonging to the region {s ∈ C ∶ Re(s) > 1/2}, the height does not have the Northcott property. Taking as context the results of the first article, we will then return, in a second article, to the initial situation of Dedekind zeta functions to study the question on this extended domain. The results on the Northcott property are different and the scenario on function fields is found to be stained with non-Northcott disks around the negative integers. These two articles will be preceded by an introduction to the theory of number fields and function fields up to the definition of their respective zeta functions. Finally, we will also include a discussion of the differences between these two theories culminating in alternative definitions of their zeta function. Ultimately, this introduction will provide all the tools necessary to attack the questions on the Northcott property discussed in the articles.

In this dissertation, we consider four cases of Boyd’s conjectures for the Mahler measure of polynomials. The first case involves a polyno- mial defining a genus 1 curve, two other cases cover genus 2 curves, and the final case deals with a genus 3 curve. For the case of the genus 1 curve, we study an identity conjectured by Boyd and proven by Boyd and Rodriguez-Villegas. We find an expression of the Mahler measure given by a linear combination of some values of the Bloch-Wigner dilogarithm. Combining this with the result proven by Boyd and Rodriguez-Villegas, we can establish some identities among different values of the Bloch-Wigner dilogarithm. For the problems related to the genus 2 curves, we use the elliptic regulator to recover some identities between Mahler measures involving certain families of genus 2 curves that were conjectured by Boyd and proven by Bertin and Zudilin by differentiating the parameter in the Mahler measure formulas and using hypergeometric identities. For the case involving the genus 3 curve, we use the elliptic regulator to prove an entirely new identity between the Mahler measures of a genus 3 polynomial family and of a genus 1 polynomial family that was initially conjectured by Liu and Qin. Since our proofs for the cases of genus 2 and 3 curves involve the regulator, they yield light into the relation of the Mahler measures of the genus 2 or 3 families with special values of the L-functions associ- ated to the genus 1 families.

The main purpose of this thesis is to compute the logarithmic Mahler measure of the three variable polynomial family xn + 1 + (xn−1 + 1)y + (x − 1)z. In order to accomplish this, we integrate regulators defined on polylogarithmic motivic complexes. To understand these regulators, we explore the properties of polylogarithms and show some polylogarithmic identities. The regulators are then applied to simplify the integrand. Our result is a formula relating the Mahler measure of the family of polynomials to the Bloch–Wigner Dilogarithm and the Riemann zeta function.

A positive integer n is said to be congruent if it is the area of a right triangle whose sides are all of rational length. The task of finding which integers are congruent is an old and famous yet still open question in arithmetic geometry called the congruent number problem. It is linked to the theory of elliptic curves as the integer n is congruent if and only if the elliptic curve y²=x³-n²x has a rational point of infinite order. The link between congruent numbers and elliptic curves enables the application of techniques from algebraic geometry to study the problem. One of these methods is the concept of Monsky matrices that can be used to calculate the size of the 2-Selmer group of the elliptic curve y²=x³-n²x. One can use these matrices in order to find new infinite families of non-congruent numbers. The connection to elliptic curves also introduces generalizations to the congruent number problem. For example, one may consider the θ-congruent number problem which studies triangles with a fixed angle of θ instead of only right triangles. This problem is also related to elliptic curves and the concept of Monsky matrices can be generalized to it. In fact, Monsky matrices can be generalized to any elliptic curve that has a Legendre form over the rationals. The goal of this thesis is to construct such a generalization and then to apply it to relevant problems in arithmetic geometry to efficiently reprove old results and find new ones.

In this thesis we consider a variation of the Mahler measure where the defining integral is performed over a more general torus. Our work is based on a tempered family of polynomials originally studied by Boyd, Boyd P_k (x, y) = x + 1/x + y + 1/y + k with k ∈ R_{>4}. For the k = 4 case we use special values of the Bloch-Wigner dilogarithm to obtain the Mahler measure of P_4 over an arbitrary torus (T_ {a, b})^2 = {(x, y) ∈ C* X C* : | x | = a, | y | = b } with a, b ∈ R_{> 0}. Next we establish a relation between the Mahler measure of P_8 over a torus(T_ {a, √a} )^2 and its standard Mahler measure. The combination of this relation with results due to Lalin, Rogers, and Zudilin leads to a formula involving the generalized Mahler measure of this polynomial given in terms of L'(E, 0). In the end, we propose a strategy to prove some similar results for the general case k > 4 over (T_ {a, b})^2 with some restrictions on a, b.

This master’s thesis goal is to give a simple and brief introduction about Mahler measure and its connections with elliptic curves L-functions. This theory culminates with the Bloch-Beı̆linson conjectures which we try to explain at the end of chapter 2, the first two chapters serving to introduce the necessary requirements to understand them and as a stepping stone to this master’s main question which is to find a link between the Mahler measure of y 2 + 4xy + 2y − x 3 and the L-function associated to it. For this purpose, we see that the conjectured relation given by D. Boyd [1] is false but we still study the homology cycles and integration paths associated to the elliptic curves y 2 + 4xy + 2y − x 3 = 0 and (1 + x)(1 + y)(x + y) + 2xy = 0.

The objective of this thesis is to count monic irreducible polnomials over a finite field under some conditions on the coefficients of the polynomial. These conditions will be simply to fix some coefficients, or to fix their sign, cubicity or quarticity.

The objective of this thesis is to count the monic irreducible polynomial over finite field with some conditions related to coefficient. First, we will determine the trace of the polynomial. Thereafter, we will elect the cotrace when the trace is already fixed to zero. Finally, we will discuss the case where the trace and the constant term are fixed at the same time

Bloch and Beilinson conjectured many relations regarding the regulator of a modular curve. This function from the algebraic K-theory of the modular curve is supposed to be related to special values of L functions. Let N be a positive integer et consider the congruence subgroup $\Gamma_0(N)$. This thesis relates explicitly the regulator of the modular curve $X_0(N)$ applied to some newform with a special value of the newform's L function.

This thesis applies to study first, in part 1, the Mahler measure of polynomials in one variable. It starts by giving some definitions and results that are important for calculating this height. It also addresses the topic of Lehmer’s question, an interesting conjecture in the field, and it gives some examples and results aimed at resolving the issue. The extension of the Mahler measure to several variable polynomials is then considered including the subject of limit points with some examples. In the second part, we first give definitions of a higher order for the Mahler measure, and generalize from single variable polynomials to multivariable polynomials. Lehmer’s question has a counterpart in the area of the higher Mahler measure, but with totally different answers. At the end, we reach our goal, where we will demonstrate the generalization of a theorem of Boyd-Lawton. This theorem shows a relation between the limit of Mahler measure of multivariable polynomials with Mahler measure of polynomials in one variable. This result has implications in terms of Lehmer's conjecture and serves to clarify the relationship between the Mahler measure of one variable polynomials, and the Mahler measure of multivariable polynomials, which are very different.

The 2-higher and 3-higher Mahler measure of some rational functions are given in terms of special values of the Riemann zeta function, a Dirichlet L-function and multiple polylogarithms. Our results generalize those obtained in [10] for the classical Mahler measure. We improve one of our results by providing a reduction for a certain linear combination of multiple polylogarithms in terms of Dirichlet L-functions. We conclude by giving a complete reduction of a special case.