Klaas-Tido Rühl


professional CV

07/2011 - 11/2020
REFUSiON GmbH, Zürich, Switzerland:
software development, project management, system administration,
specialized in Magento eCommerce solutions, developing and maintaining Web applications
04/2010 – 05/2011
routeRANK Ltd., Lausanne, Switzerland:
developer and lead developer (since 01/2011),
using Ruby, PHP, JavaScript, SQL, HTML, CSS,
developing, maintaining, and optimizing a multi-modal travel planning tool, development of new features,
additional responsibilities: research, scientific publications, database administration, server administration, project management
09/2006 – 04/2010
Ecole Polytechnique Fédérale de Lausanne, Switzerland:
assistant to Prof. Eva Bayer-Fluckiger,
teaching assistant for various courses in mathematics
04/2005 – 07/2005
& 04/2003 – 03/2004
& 04/2002 – 09/2002
Georg-August Universität Göttingen, Germany:
teaching assistant for various courses in mathematics
10/2000 - 03/2002
Prof. Schumann GmbH, Göttingen, Germany:
developer, using Java,
developing and maintaining a credit risk management software

academic CV

public Ph.D. defense,
obtainment of doctorate
2 weeks research stay (in the context of the GTEM network) at the Université Pierre et Marie Curie (Paris 6), France
09/2008 - 10/2008
5 weeks research stay (in the context of the GTEM network) at the University of Bordeaux 1, France
03/2008 - 06/2008
3 months research stay (in the context of the GTEM network) at the University of Leiden, Netherlands
08/2007 - 07/2010
Marie Curie Actions fellow, ESR (Early Stage Researcher) of the EPFL node of the GTEM network (Galois Theory and Explicit Methods)
05/2007 - 04/2010
member of the doctoral school at the EPFL, Lausanne, Switzerland
09/2006 - 07/2010
graduate studies in mathematics and assistant at the EPFL, Lausanne, Switzerland
08/2005 - 05/2006
graduate studies in mathematics at UC Berkeley, California, USA, through the EAP
graduation ("Diplom")
intermediate examination ("Vordiplom")
10/1999 - 02/2005
studies in mathematics (minor: computer studies) at the Georg-August-Universität, Germany



Ph.D. thesis

Annihilating Polynomials for Quadratic Forms

Already Ernst Witt noticed, that the Witt ring (of quadratic forms) of a field is integral (over the integers), but it took until 1987 for David Lewis to construct specific polynomials (with integer coefficients), which annihilate the isometry and equivalence classes of quadratic forms of a given dimension over an arbitrary field. In this thesis we study annihilating polynomials for quadratic forms (i.e. for the isometry or equivalence class of a quadratic form). In particular we study the annihilating ideal for a given quadratic form, i.e. the ideal consisting of all annihilating polynomials for that quadratic form. It is our aim to achieve a general understanding of the structure of these annihilating ideals, and to develop methods that allow us to determine annihilating ideals for isometry and equivalence classes of quadratic forms over a given field.

download: Annihilating Polynomials for Quadratic Forms", version from April 11, 2010

diploma thesis

Generic Splitting of Quadratic Forms

This thesis is a rather substantial recapitulation of the progress the theory of generic splitting of quadratic forms has made since it was first introduced in 1976 by Manfred Knebusch. The thesis deals with the results about this theory that can be obtained with elementary methods. Of special importance are the results by Detlev Hoffmann, since with the help of them it becomes possible to simplify the proofs of a numbers of less recent results.

download: Generische Zerfällung Quadratischer Formen"

selected talks