Karim Belabas

ORCID: 0000-0002-8237-7500
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About
Contact & Profiles
Research Areas
  • Algebraic Geometry and Number Theory
  • Analytic Number Theory Research
  • Computability, Logic, AI Algorithms
  • Coding theory and cryptography
  • Polynomial and algebraic computation
  • Advanced Algebra and Geometry
  • History and Theory of Mathematics
  • Cryptography and Residue Arithmetic
  • Finite Group Theory Research
  • Mathematics and Applications
  • Point processes and geometric inequalities
  • Advanced Mathematical Identities
  • Geometric and Algebraic Topology
  • Numerical Methods and Algorithms
  • Matrix Theory and Algorithms
  • Limits and Structures in Graph Theory
  • Advanced Differential Equations and Dynamical Systems
  • Algorithms and Data Compression
  • Historical and Political Studies
  • Linguistics and Discourse Analysis
  • Geometric Analysis and Curvature Flows
  • graph theory and CDMA systems
  • Digital Filter Design and Implementation
  • Logic, Reasoning, and Knowledge
  • Mathematical and Theoretical Analysis

Université de Bordeaux
2010-2025

Institut de Mathématiques de Bordeaux
2011-2024

Laboratoire de Mathématiques
2021

Polygon Physics (France)
2021

Laboratoire de Mathématiques de Besançon
2021

Université de franche-comté
2021

Centre National de la Recherche Scientifique
2001-2018

Institut national de recherche en informatique et en automatique
2013-2018

Numerical Method (China)
2018

Laboratoire de Mathématiques d'Orsay
2003-2010

The workshop brought together people attacking key modern problems in number theory via techniques involving concrete or computable descriptions. Here, was interpreted broadly, including algebraic and analytic theory, Galois arithmetic of varieties, zeta L-functions their special values, modular forms functions.

10.4171/owr/2024/40 article EN cc-by-sa Oberwolfach Reports 2025-02-14

We present a very fast algorithm to build up tables of cubic fields. Real fields with discriminant <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="10 Superscript 11"> <mml:semantics> <mml:msup> <mml:mn>10</mml:mn> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>11</mml:mn> </mml:mrow> </mml:msup> <mml:annotation encoding="application/x-tex">10^{11}</mml:annotation> </mml:semantics> </mml:math> </inline-formula> and complex down...

10.1090/s0025-5718-97-00846-6 article EN Mathematics of Computation 1997-01-01

We prove that van Hoeij's original algorithm to factor univariate polynomials over the rationals runs in polynomial time, as well natural variants. In particular, our approach also yields time complexity results for bivariate a finite field.

10.5802/jtnb.655 article EN Journal de Théorie des Nombres de Bordeaux 2009-01-01

This note presents our implementation in the PARI/GP system of various arithmetic invariants attached to logarithmic classes and units number fields. Our algorithms simplify improve on works Diaz y Diaz, Pauli, Pohst, Soriano second author.

10.5802/pmb.o-1 article EN Publications mathématiques de Besançon 2016-12-13

We describe practical algorithms from computational algebraic number theory, with applications to class field theory. These include basic arithmetic, approximation and uniformizers, discrete logarithms computation of fields. All have been implemented in the Pari/Gp system.

10.5802/jtnb.433 article EN Journal de Théorie des Nombres de Bordeaux 2004-01-01

We obtain the first known power-saving remainder terms for theorems of Davenport and Heilbronn on density discriminants cubic fields mean number 3-torsion elements in class groups quadratic fields. In addition, we prove analogous error quartic 2-torsion These results analytic continuation related Dirichlet series to left line R(s)=1.

10.1215/00127094-2010-007 article EN Duke Mathematical Journal 2010-04-28

10.1016/j.jsc.2003.09.003 article EN publisher-specific-oa Journal of Symbolic Computation 2003-12-23

10.1023/b:kthe.0000028979.91416.00 article EN K-Theory 2004-03-01

Assuming the Generalized Riemann Hypothesis, Bach has shown that ideal class group $\mathcal {C}\ell _{K}$ of a number field $K$ can be generated by prime ideals having norm smaller than $12\big (\log |\mathrm {Discriminant}(K)|\big )^2$. This result is essential for computation and units Buchmann’s algorithm, currently fastest known. However, once _K$ been computed, one notices this bound could have replaced much value, so work saved. We introduce here short algorithm which allows us to...

10.1090/s0025-5718-07-02003-0 article EN public-domain Mathematics of Computation 2007-12-12

Davenport and Heilbronn defined a bijection between classes of binary cubic forms fields, which has been used to tabulate the latter. We give simpler proof their theorem then analyze improve table-building algorithm. It computes multiplicities <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper O left-parenthesis upper X right-parenthesis"> <mml:semantics> <mml:mrow> <mml:mi>O</mml:mi> <mml:mo stretchy="false">(</mml:mo>...

10.1090/s0025-5718-04-01632-1 article EN publisher-specific-oa Mathematics of Computation 2004-01-30

10.1007/s40687-018-0155-z article EN Research in the Mathematical Sciences 2018-08-22

These notes contain extended abstracts on the topic of explicit methods in number theory. The range topics includes Sato-Tate conjecure, Langlands programme, function fields, L-functions and many other topics.

10.4171/owr/2011/35 article EN Oberwolfach Reports 2012-04-11

Nous calculons la densité des discriminants corps sextiques galoisiens de groupe S 3 , démontrant un nouveau cas conjecture Malle ainsi qu'un particulier sa généralisation par Ellenberg et Venkatesh. Plus généralement, nous étudions cubiques dans une progression arithmétique, avec zone d'uniformité plus large possible. We compute the density of Galois sextic fields with group thereby proving a new case Malle's as well special its generalization by and Further, we study cubic in an arithmetic...

10.1142/s1793042110003605 article FR International Journal of Number Theory 2010-11-01

Let M be a geometrically finite pinched negatively curved Riemannian manifold with at least one cusp. The asymptotics of the number geodesics in starting from and returning to given cusp, horoballs parabolic fixed points universal cover , are studied this paper. case SL(2, ℤ), Bianchi groups, is developed.

10.1112/s0024609301008244 article EN Bulletin of the London Mathematical Society 2001-09-01

Let K be a global field and f in K[X] polynomial. We present an efficient algorithm which factors polynomial time.

10.48550/arxiv.math/0409510 preprint EN other-oa arXiv (Cornell University) 2004-01-01

Assuming the Generalized Riemann Hypothesis, Bach has shown that one can calculate residue of Dedekind zeta function a number field <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper K"> <mml:semantics> <mml:mi>K</mml:mi> <mml:annotation encoding="application/x-tex">K</mml:annotation> </mml:semantics> </mml:math> </inline-formula> by clever use splitting primes alttext="p greater-than upper X"> <mml:mrow> <mml:mi>p</mml:mi>...

10.1090/s0025-5718-2014-02843-3 article EN publisher-specific-oa Mathematics of Computation 2014-05-07

The Cohen–Lenstra–Martinet heuristics give precise predictions about the class groups of a ’random‘ number field. 3-rank quadratic fields is one few instances where these have been proven. We prove that, in this case, rate convergence at least sub-exponential. In addition, we show that defect appearing Scholz‘s mirror theorem equidistributed with respect to twisted Cohen–Lenstra density.

10.1023/a:1000949724172 article EN Compositio Mathematica 1999-01-01

Call h 3 * (Δ) the number of cube roots unity in class group ℚ(Δ), where Δ is a fundamental discriminant. Davenport and Heilbronn computed mean value these numbers when tends to ±∞. The author gives general geometric argument yielding an explicit bound for error term, with additional possibility restricting arithmetic progressions. Sieve techniques then produce results about 3-parts groups Cl (ℚ(Δ)), P k almost-prime order k. In this way, one controls simultaneously both 2-rank 3-rank...

10.5802/aif.1535 article EN Annales de l’institut Fourier 1996-01-01
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