Math Colloquium

Description
Speaker: Willem H. Haemers
Tilburg University, The Netherlands


Title: Are almost all graphs determined by their spectrum?

Abstract: An important class of problems in mathematics deals with the reconstruction of a

structure from the eigenvalues of an associated matrix. The most famous such prob-
lem is: ‘Can one hear the shape of a drum?’. Here we deal with the question: ‘Which

graphs are determined by the spectrum (eigenvalues) of its adjacency matrix’? More

in particular we ask ourselves whether this is the case for almost all graphs. There

is no consensus on what the answer should be, although there is a growing number

of experts that expect it to be affirmative. In this talk we will present several re-
sults related to this question. This includes constructions of cospectral graphs and

characterizations of graphs by their spectrum. Some of these results support an

affirmative answer, some support the contrary. It will be explained why the speaker

believes that it is true.
Description
Ramanujan Hall
Date
Wed, February 8, 2017
Start Time
4:00pm-5:00pm IST
Duration
1 hour
Priority
5-Medium
Access
Public
Created by
DEFAULT ADMINISTRATOR
Updated
Mon, February 6, 2017 9:52am IST