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Algebraic Geometry and Computer Algebra
Details | Lectures | The Group | Exemplary Schedule | Winter term 1999/2000 | Summer term 2000
Algebraic Geometry and Computer Algebra
Worldwide there are but few universities where the relation between theoretical research in algebraic geometry, complex analysis, singularity theory and computer algebra together with industrial applications is as well developed as in Kaiserslautern.
This fact is mirrored in teaching: courses are offered in these fields guiding the student to interesting problems in theory and applications.
Accompanying lectures in algebra, topology and differential geometry at the same time open wider perspectives on mainstream mathematics.
Algebraic Geometry is one of the oldest of the classical mathematical disciplines. Traditionally, it deals with the study of algebraic varieties, that is, the zero-sets of (systems of) polynomial equations, in particular, with their geometry. There are deep connections with various other areas of mathematics and theoretical physics, such as complex analysis, number theory, topology, differential geometry or string theory. This interaction makes algebraic geometry a highly dynamic subject and relevant for many "real world" problems.
The development of algebraic geometry throughout the past centuries occurred in waves and was influenced by different schools, each of them using a different language. In the second half of this century, the foundations of algebraic geometry have been completely reformulated, introducing the language of schemes, vector bundles and sheaf cohomology. This has led to many new results and a deeper understanding of classical ones; it has allowed simplification of proofs as well as substantial generalisation of results.
The main task of algebraic geometry, the investigation of the global and the local structure of varieties brought forth the discipline of singularity theory. It is concerned with the study of the local behaviour of varieties at non-smooth points (which are decisive for the structure of a variety and resist a numerical treatment) and has applications, for instance, in the study of dynamical systems.
Current research in algebraic geometry as performed in Kaiserslautern includes, for example, the construction and the study of moduli spaces, i.e., varieties whose points represent the objects of interest, e.g., singularities, varieties of a certain class, vector bundles, sheaves, etc.

Moebius strip inside a vector bundle
In algebraic geometry, the computer has become an increasingly important tool for complicated calculations. Computer algebra is concerned with the development of efficient algorithms and their implementation. It emerged in the 1970's and gained popularity via computer algebra systems such as Macsyma, Reduce, Maple, Mathematica, MuPAD, etc. These systems have become indispensable in research, teaching and industrial development.
The computer algebra system SINGULAR, which has been developed in Kaiserslautern, has been designed for computations in commutative algebra, algebraic geometry and singularity theory. Its main features include the computation of standard bases, syzygies and the factorisation of multivariate polynomials over several ground fields. Its implementation of the Buchberger algorithm is one of the fastest worldwide. SINGULAR offers a C-like programming language and includes many libraries for applications in singularity theory and algebraic geometry. In joint projects with microelectronics, SINGULAR is also used for dealing with problems concerning analog circuits.
The Kaiserslautern research groups in algebraic geometry, singularity theory and computer algebra are prominent members of German and European networks and maintain research contacts worldwide. They are actively participating in the network EAGER for projective algebraic geometry, which consists of approximately 50 nodes in Western Europe. In singularity theory, the Kaiserslautern group is a member of the European Singularity Net ESN. The Computer Algebra group leads the European POSSO-project and participates in the German DFG-Schwerpunkt "Effiziente Algorithmen für diskrete Probleme und ihre Anwendungen".
There are but a few universities in the world where the theoretical research in algebraic geometry is linked as well with industrial applications as it is in Kaiserslautern. This fact is reflected in teaching. The programme "Mathematics International" with its specialisation "Algebraic Geometry and Computer Algebra" offers various courses in the above fields leading the student to interesting theoretical and practical problems. Moreover, the students may also participate in the activities of the Centre of Computer Algebra, present at the Department of Mathematics. Additional lectures in algebra, topology, differential geometry, etc. provide background knowledge and guarantee a broad education in contemporary mathematics. Moreover, there is an abundance of seminars, tutorials and colloquia, including talks by guest speakers, which provide a stimulating environment for research.
Prof. Dr. G.-M. Greuel, Prof. Dr. G. Pfister, Prof Dr. G. Trautmann, PD Dr. K. Wirthmüller, Dr. C. Lossen, Dr. B. Kreußler, Dr. J. Zintl and assistants.
The following list is a selection of the offered lectures within the specialization "Algebraic Geometry and Computer Algebra". There may be some fluctuations due to a variety of reasons.
| Short Cut | Lectures |
| AG01 | Introduction to Algebraic Geometry |
| Affine rings and affine algebraic sets; Noetherian rings; Hilbert's Nullstellensatz; algebraic varieties; graded rings and projective algebraic varieties; local rings and singularities; Weierstraß preparation theorem; dimension theory and primary decomposition; complex analytic sets; computational aspects of all concepts | |
| AG02 | Complex Differential Geometry |
| Complex manifolds; almost complex structures; complex submanifolds and analytic sets; complex tori; projective algebraic manifolds; differentiable and holomorphic vector bundles; Dolbeault cohomology; Kodaira's vanishing theorem; Serre duality; Kähler manifolds; Hodge decompoition; Chern classes; differential operators; Hermite-Einstein vector bundles; introduction to variation of Hodge structures | |
| AG03 | Computational Commutative Algebra |
| Polynomial rings; power series rings; Weierstraß preparation theorem; polynomial division and consequences (Noether normalization, implicit function theorem); dimension theory; Monomial orderings in polynomial and powerseries rings; Buchberger algorithm and some applications | |
| AG04 | Algebraic Geometry |
| Sheaves; ringed spaces; coherent and quasicoherent sheaves; schemes and its properties; complex spaces; singularities; sheaf cohomology; curves; theorem of Riemann-Roch; applications; computational aspects of all concepts | |
| AG05 | Algebraic Surfaces |
| Intersection theory for surfaces; Picard group; Riemann-Roch; birational maps; ruled surfaces; rational surfaces; Castelnuovo's theorem; Kodaira dimension; classification of surfaces | |
| AG06 | Singularity Theory |
| Singularities of hypersurfaces; finite determinacy; classification of simple singularities; finite mapping theorem; invariants of curve and surface singularities; computational aspects of all concepts | |
| AG07 | Moduli Spaces |
| Actions of algebraic groups; affine quotients and Hilbert's fourteenth problem; linearisation of algebraic group actions; stability and projective quotients; geometric invariant theory; change of polarisation and flips; coarse and fine moduli spaces; moduli spaces of vector bundles and coherent sheaves; selected examples of moduli spaces; holomorphic constructions of moduli spaces | |
| AG08 | Algebraic Curves |
| Ramified coverings; the Riemann-Hurwitz formula; the genus formula; Abels theorem; linear systems on curves; the Riemann-Roch formula; the Plücker formulas; elliptic curves | |
| AG09 | Deformation Theory |
| Deformations of hypersurfaces and complete intersections; abstract deformation theory of maps and spaces; relations between local and global deformations; relations between deformation and representation properties; moduli questions; computational aspects of all concepts | |
| AG10 | Intersection Theory |
| Varieties and schemes; morphisms; Grassmann and flag varieties; affine and projective bundles; rational equivalence; divisors; Segre and Chern classes; cones; intersection products; intersection multiplicities; Chow rings; Riemann-Roch theorem; selected examples | |
| AG11 | Complex Surfaces |
| Cohomology of surfaces; curves on surfaces; Riemann-Roch; Kodaira dimension; Kähler surfaces; Hodge theory; GAGA theorems and projectivity | |
| AG12 | Algebraic Geometry II |
| schemes; sheaf cohomology; divisors; base change theorems; blowing up; differential forms on singularities; complex analytic spaces; curves and surfaces; computational aspects of all concepts | |
| AG13 | Complex Analysis |
| Holomorphic functions of several variables; complex manifolds; sheaves and cohomology; ringed spaces; analytic sets; Stein spaces | |
| AG14 | Computer Algebra |
| Multivariate factorization of polynomials; standard bases; characteristic sets; algorithms on primary decomposition; syzygies; normalisation | |
| RM01 | Algebraic Topology |
| Homological algebra; homology; homotopy invariance of homology; excision; Mayer-Vietoris-sequence; Eilenberg-Steenrod axioms; Lefschetz fixed point theorem; Künneth theorem; cohomology; orientation; products; duality on manifolds | |
| RM02 | Differential Topology |
| An introduction to the basic ideas and methods of differential topology, to be illustrated by their application to the classification of compact surfaces. Topics include ODEs on differential manifolds, tubular neighbourhoods and collars, connected sum of manifolds, Morse functions, and complex line bundles on surfaces and their Euler number | |
| RM03 | Algebraic Groups |
| Algebraic varieties and schemes; flag varieties; affine algebraic groups; classical groups; actions of algebraic groups; Lie algebras of algebraic groups; adjoint representation; homogeneous spaces; Jordan-Chevalley decomposition; diagonalizable groups; solvable groups; Borel subgroups; parabolic subgroups; root systems; reductive groups; semisimple groups; introduction to representation theory; Borel-Bott-Weil theory | |
| RM04 | Homological Algebra (Seminar) |
| Complexes; resolutions; cohomology; derived functors; double complexes; spectral sequences; Leray spectral sequence; Grothendieck spectral sequence; applications | |
| RM05 | Differential Geometry |
| An introduction to differential geometry with a view towards global aspects. Among the topics will be Riemannian manifolds, connections on vector and principal bundles, holonomy groups, curvature, characteristic classes, Yang-Mills equation and instantons. | |
| RM06 | Invariant Theory |
| Reductive groups; categorial, geometric and good quotients; the finitness theorem; stability and semistability; examples and applications to moduli problems | |
| RM07 | Symmetric Spaces |
| The aim of this course is to explain the classification of symmetric spaces. It will, to some extent, build upon the previous one (Differential Geometry) but will independently present the necessary background from Lie theory | |
| RM08 | Morse Theory |
| Critical points; Morse functions; homotopy type in terms of critical values; the Morse inequalities; applications to algebraic varieties: Lefschetz theorem on hyperplane sections |
Exemplary Schedule for students who started in the winter term 1997/98
This is an exemplary schedule for the study programme Mathematics International within the scope of the specialization "Algebraic Geometry and Computer Algebra".
| Semester | Specialization Algebraic Geometry |
Pure Mathematics | Applied Mathematics | Computer Science | Credits |
| . | German Language Course | . | |||
| 1 | AG01* (4) Introduction to Algebraic Geometry AG02
(2) AG03 (2) |
RM01 (4) Algebraic Topology RM02 (2) Differential Topology |
Mandatory* (4) | . | 12 |
| 2 | AG04* (4) Algebraic Geometry AG05 (2) Algebraic Surfaces |
RM03 (4) Algebraic Groups RM04 (2) Homological Algebra (Seminar) |
RM09* (4) Computer Algebra |
. | 12 |
| 3 | AG06 (4) Singularity Theory or AG07 (4) Moduli Spaces AG08 (2) Algebraic Curves Seminar* (2) |
RM05 (4) Differential Geometry RM06 (2) Invariant Theory |
. | Mandatory* (4) | 10 |
| 4 | AG09 (2) or Deformation Theory AG10 (4) Intersection Theory AG11 (2) Complex Surfaces Seminar* (2) |
RM07 (4) Symmetric Spaces RM08 (2) Morse Theory |
. | Mandatory* (4) | 10 |
| 5 | Master Thesis* (16) | . | . | . | 16 |
| Total ** | 36 | 8 | 8 | 8 | 60 |
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