[Colloquium] Talk by Dhruv Mubayi, UIC on February 23, 2009

[Katie Casey]

DEPARTMENT OF COMPUTER SCIENCE

UNIVERSITY OF CHICAGO

Date: Monday, February 23, 2009
Time: 3:45 p.m.
Place: RY 251

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Speaker:	Dhruv Mubayi

From:		University of Illinois at Chicago

Website: 	http://www.math.uic.edu/~mubayi/

Title:  Coloring Simpler Hypergraphs

Abstract:  Improvements of the obvious lower bounds on the  
independence number
of (hyper)graphs have had impact on problems in discrete geometry,
coding theory, number theory and combinatorics. One of the most
famous examples is the result of Komlos-Pintz-Szemeredi (1982) on
the independence number of 3-uniform hypergraphs which made
important progress on the decades old Heilbronn problem.

We give a sharp upper bound on the chromatic number of simple
k-uniform hypergraphs that implies the above result as well as more
general theorems due to Ajtai-Komlos-Pintz-Spencer-Szemeredi, and
Duke-Lefmann-Rodl. Our proof technique is inspired by work of
Johansson on graph coloring and uses the semi-random or nibble
method.  This is joint work with Alan Frieze.


Refreshments will be served prior to the talk in RY 255.