Computation in Algebra and Number Theory Spring 2022

Lecturer
David Alexander Loeffler
Coordinator
Tim Gehrunger

Provisional course outline

The notes can be downloaded here.
Lecture Date Content
1 24.02. Aims of the course. Exact computation. Exact structures: \(\mathbb{Z}\), \(\mathbb{Q}\), \(\mathbb{Z}/n\), polynomials, matrices, etc. Non-example of \(\mathbb{R}\). Interval arithmetic. Polynomial root isolation and \(\bar{\mathbb{Q}}\).
2 03.03 Matrix algebra over fields, echelon form, subspaces. Matrix algebra over \(\mathbb{Z}\): Hermite and Smith form. Applications to abelian groups.
3 10.03 Univariate polynomials. Factorisation in \(\mathbb{F}_p[x]\). Extensions of finite fields, Conway polynomials.
4 17.03 Univariate polynomials over \(\mathbb{Q}\) and \(\mathbb{Z}\). Mignotte’s bound, factorisation by Hensel lifting.
5 24.03 Multivariate polynomials. Ideals. Vocabulary of algebraic geometry; affine / projective varieties. Term orderings, Groebner bases.
6 31.03 Buchberger’s algorithm; some more advanced algorithms. Elimination theory. Radicals, primary decomposition, etc.
7 07.04 More on algebraic geometry. Invariant theory (if time).
8 14.04 Elliptic curves (generalities). Elliptic curves over finite fields, applications to cryptography.
21.04 Easter break
9 28.04 Number fields I: integer rings, discriminant, ideal factorisation.
10 05.05 Number fields II: class group, unit group, regulator. Hints at class field theory.
11 12.05 Group theory: presentations of groups, coset enumeration, applications to \(\operatorname{SL}(2, \mathbb{Z})\).
12 19.05 Finite groups: representations and characters, Burnside’s algorithm.
26.05 No lecture (Ascension Day)
13 02.06 Overflow slot

Prerequisites

Algebra II, Commutative Algebra; basic notions of computer programming (e.g. first-year bachelors "Computer Science" course). Prior knowledge of algebraic number fields and/or algebraic varieties will be useful, but not absolutely necessary.

Exercises

The new exercises will be posted here.

exercise sheet example code from exercise session
Sheet 1
Sheet 2 Notes
Sheet 3 Notes
Sheet 4 Notes
Sheet 5 Notes
Sheet 6 Notes
Sheet 7 Notes
Sheet 8 Notes
Sheet 9 Notes
Sheet 10 Notes
Notes

Literature

Last updated: 02.06.2022