Laurent Bartholdi

I'm a Professor at the Mathematical Institute of the Georg-August University of Göttingen, currently on leave at École Normale Supérieure, Paris. I am also the conservator of the models collection. Here is a map of Göttingen with important mathematical places.

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Laurent Bartholdi
Office 202, Mathematical Institute
Bunsenstraße 3-5
D-37073 Göttingen
Telephone: +49 551 39 7826
Secretary: +49 551 39 7752
Facsimile: +49 551 39 22674
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Model collection 65537-gon.

Publications (HTML), Google Scholar and arXiv

Curriculum vitae:
In HTML or PDF format .
I am currently interested in understanding fractal behaviour in group theory and algebra, and its use for holomorphic dynamical systems.

Self-similar, or fractal, objects abound in mathematics; depending on context, they mean a space containing several almost disjoint copies of itself as subspaces; a group containing the direct product of copies of itself as a subgroup; or an algebra containing a matrix algebra over itself as a subalgebra. The fractalness is algebraically encoded via the collection of inclusion maps of these subobjects in their common parent.

A self-similar group may be associated with any complex dynamical system, and yields an extremely potent algebraic invariant of that dynamical system up to isotopy and conjugation. I currently explore more deeply the connection between complex dynamics and fractal groups, and use it to extend the classification of degree-two polynomials (described by points in the Mandelbrot set) to arbitrary-degree rational functions.

Mathematical events
Department colloquium
GK colloquium
Nerd score:
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Unicode cut&paste sheet.
  • The FR GAP-package, for manipulation of groups and semigroups generated by automata.
  • The IMG GAP-package, for manipulation of iterated monodromy groups and complex dynamics.
  • The Float GAP-package, for manipulation of real, complex, interval etc. floating-point numbers.
  • Göttingen collection of mathematical models
  • Slides I received from speakers in the conference "Trends and Directions in Conformal Dynamics" in Oberwolfach, October 17-21, 2008
  • Windows crashes in everyday life -- a commented photo gallery
  • Movies illustrating the "twisted rabbit" paper in progress with V. Nekrashevych.
  • How I Rank in Hell
  • My Images
  • A movie I made of the Schreier graph of the Gupta-Sidki group, in avi and MPEG-1format.