Seminar series
Date
Tue, 05 Nov 2013
Time
14:30 -
15:00
Location
L5
Speaker
L. Nick Trefethen
Organisation
University of Oxford
Crouzeix's conjecture is an exasperating problem of linear algebra that has been open since 2004: the norm of p(A) is bounded by twice the maximum value of p on the field of values of A, where A is a square matrix and p is a polynomial (or more generally an analytic function). I'll say a few words about the conjecture and
show the beautiful proof of Pearcy in 1966 of a special case, based on a vector-valued barycentric interpolation formula.