Type: Seminar

Modified: Mon 17 Mar 2014 1046; Mon 17 Mar 2014 1303; Mon 17 Mar 2014 1349; Mon 17 Mar 2014 1350

Distribution: World

Expiry: 7 Apr 2014

Auth: zhangou@como.maths.usyd.edu.au

The original talk by Professor Feng Luo is cancelled due to visa reason. Sorry for any inconvenience. However, we have the following talk offered by Stephan Tillmann. It is supposed to warm up people for the incoming workshop in Week 5. Time: Tuesday, March 18, 12NOON--1PM. Room: Carslaw 535A. Title: Normal Surfaces in 3-Manifolds: Algorithms, Experiments and Questions ABSTRACT: the theory of normal surfaces, introduced by Kneser in the 1920s and further developed by Haken in the 1960s plays a crucial role in 3-manifold topology. Normal surfaces allow topological problems to be translated into algebraic problems or linear programs, and they are the key to many important advances over the last $50$ years, including the solution of the unknot recognition problem by Haken, the 3-sphere recognition problem by Rubinstein and Thompson and the homeomorphism problem by Haken, Hemion and Matveev. In this talk, I will summarise Haken’s blueprint for algorithmic 3-manifold topology, discuss the "difficulty" of the computational problems from a theoretical and experimental perspective and state some open questions and challenges. ********************************************************************** Speaker: Prof. Feng Luo (Rutgers University) http://www.math.rutgers.edu/~fluo/ Time: Tuesday, March 18, 12NOON--1PM. Room: Carslaw 535A. Lunch: seminar lunch is right after the talk at Law Annex Cafe, with reservation at 1:10PM. ---------------------------------------------- Title: A Discrete Uniformization Theorem for Polyhedral Surfaces ABSTRACT: we introduce a discrete conformality for polyhedral metrics on surfaces. It is shown that each polyhedral metric on a surface is discrete conformal to a constant curvature polyhedral metric which is unique up to scaling. Furthermore, the constant curvature metric can be found by a finite dimensional variational principle. This is a joint work with David Gu, Jian Sun and Tianqi Wu. ---------------------------------------------- Seminar website: http://www.maths.usyd.edu.au/u/SemConf/Geometry/