Graduiertenkolleg: Methods for Discrete Structures

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Monday Lecture and Colloquium

Monday, May 13, 2013

Technische Universität Berlin
Fakultät II, Institut für Mathematik
Str. des 17. Juni 136
10623 Berlin
room MA 041

Lecture - 14:15

Matthias Kriesell - TU Ilmenau

On the Structure of Graphs of Minimum Degree at least 4

We outline a proof that for every vertex x of a 4-connected graph G there exists a subgraph H in G isomorphic to a subdivision of the complete graph K4 on four vertices such that G - V(H) is connected and contains x.

Extended abstract as [pdf]

Colloquium - 16:00

Kaie Kubjas - Freie Universität Berlin

Ehrhart polynomials, group-based models and Berenstein-Zelevinsky triangles

Group-based models are statistical models originating from evolutionary biology. There is a lattice polytope associated with each group-based model and tree. For the simplest group-based model, the Jukes-Cantor binary model, Buczynska and Wisniewski showed that the Ehrhart polynomial of this lattice polytope depends only on the number of leaves of the tree and not on its shape. We discuss the possibilities of generalizing this result and connections between group-based models and Berenstein-Zelevinsky triangles. This talk is based on joint work with Chris Manon.

Letzte Aktualisierung: 02.05.2013