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Seminář z algebry - 9.1.2020 PDF Tisk

Další seminář z algebry se koná 9.1.2020 od 13.00 v posluchárně M5.

S. Henry

Polygraphs and homotopy polygraphs

Abstrakt:
Polygraphs (or computades) are the most general notion of diagram generating strict infinity categories. Some people have believed in the past that they were a presheaves category, but this was proved to be false by Makkai and Zawadowski.
After a quick introduction to polygraphs and why they are not a  presheaves category, I'll show that if one defines a homotopy theoretic (or infinity categorical) version of polygraphs then they form an infinity presheaves category. More generally I'll associate to any strongly cartesian monad acting on an infinity topos an infinity category of polygraphs which is itself an infinity topos.

Aktualizováno Úterý, 07 Leden 2020 11:20
 
MUNI Seminar series - Noga Alon - List Coloring PDF Tisk

Seminář se koná 18.12.2019 od 16:30 v Mendelově muzeu.

Noga Alon

List Coloring

Abstract:

The list chromatic number of a graph G is the minimum k so that for every assignment of a list of k colors to any vertex of G there is a  vertex coloring assigning to each vertex a color from its list so that adjacent vertices get distinct colors. This notion was introduced by Vizing and by Erdős, Rubin and Taylor in the late 70s and its study combines combinatorial, probabilistic and algebraic techniques.

Its natural extension to hypergraphs is closely related to questions in Euclidean Ramsey Theory.

I will discuss several old and new problems and results in the area focusing on a recent work with Briceno, Chandgotia, Magazinov and Spinka motivated by questions in statistical physics regarding vertex colorings of the d-dimensional lattice.



Aktualizováno Středa, 18 Prosinec 2019 12:02
 
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