CIMPA-ICTP research school on
Artin L-functions, Artin's primitive roots conjecture and applications
Nesin Mathematics Village, Şirince, Turkey.
May 29th - June 9th 2017
Home Courses Notes Lecturers Schedule


Representation Theory of finite groups (10 hours)
Lecturers: Marina Monsurrò and Anne Queguiner-Mathieu
Basic facts on Linear representations and characters. Frobenius correspondence. Degree of a representation. Integrality properties of characters. Induced representations. Artin theorem and Brauer theorem. Rationality questions. Brauer theory. Definition of Artin L-functions. Artin conjecture. Zeros and poles of Artin L-functions. Applications of Brauer theorem on Artin L-functions
L-functions and ζ-functions (6 hours)
Lecturer: Michel Waldschmidt
Definition of the Riemann zeta function and Dirichlet L-functions. Elementary analytic properties. Values at even integers, Euler product. Functional equation. Vertical distribution of the zeros. Hadamard product expansion. The Riemann hypothesis. Other examples of L-functions and ζ-functions. L-functions coming from geometry. The Selberg class of L-functions.
Chebotarev Density Theorem (11 hours)
Lecturers: Nathan Jones and Adriana Salerno
Review of algebraic number thoery: Number fields and their ring of integers. Extension of number fields: Decomposition and ramification, the ramification index and the residue class degree of a prime ideal: their definitions and relations. Galois extensions, spilt and inert primes. The discriminant of an extension. Characterization of ramified prime ideals as those dividing the discriminant. Explicit theory for quadratic and cubic number fields. Definition of the inertia group and the decomposition group and the Frobenius symbol. The Chebotarev density theorem.
Elliptic curve analogues (10 hours)
Lecturers: Alina Cojocaru and Valerio Talmanca
Elliptic curves: Addition law on a plane cubic in Weierstrass form. Abstract elliptic curves and their planar model. Rational points on an elliptic curve. Elliptic curves over finite fields: the Weil bound for the number of points. Reduction of elliptic curves modulo a prime: first properties and the standard short exact sequence. Definition of good and bad reduction of an ellptic curve. Definition of the L-function of an elliptic curve defined over ther rationals. Primitive points modulo a prime. The Lang-Trotter conjecture on the density of primitive points. Reduction modulo a prime
Distribution of primes (6 hours)
Lecturer: Francesco Pappalardi

We shall first cover the basics of the Theory of Distribution of prime numbers. This will include the proof to the Chebicev Theorem, the Mertens Theorems and the Dirichlet Theorem for primes in arithmetic progressions.

Next we concentrate on the Riemann zeta function discussing its fundamental properties following the original paper by Riemann (Functional equation, Hadamard product expansion, Vertical distribution of the zeros and zero free regions). Time will force us to omit several proofs but we will emphasise the link between the position of the zeros of zeta and the distribution of prime numbers.

We shall conclude explaining how the above framework can, to some extent, be generalized to other type of L-functions, including Artin L-functions.
L-functions associated to motives(6 hours)
Lecturers: Fernando Rodriguez Villegas
  • Zeta functions of varieties over finite fields.
  • Interpretation in terms of the Frobenius automorphism.
  • Heuristics on motives based on concrete examples (including hypergeometric motives).
  • Global L-function associated to a motive: Euler factor at infinity, at good and bad primes, conductor, functional equation, etc.
Hooley's Theorem and quasi resolution(5 hours)
Lecturer: Cihan Pehlivan
Basic properties of primitive roots. History of the Artin Conjecture. Kummerian Extension. Explicit Chebotarev for Kummerian Extensions. Consequences of the GRH. The proof of Hooley's Theorem. Sketch of the proof of the quasi resolution of the Artin Conjecture by Gupta, Murty and Heath--Brown.