Title: Hadamard matrices and spherical designs

Speaker: Patrick Solé (Institut de Mathématiques de Marseille, Marseilles, France)

Time: 4:00 p.m. -5:00 p.m., June 7

Place: Room 801, Management R & D Building.

Abstract:Hadamard codes over finite rings are explored wrt their covering radius for the chinese euclidean distance.Generalized bent sequences, when they exist, provide a lower bound. Upper bounds are obtained by considering a spherical code attached to Hadamard matrices of Butson type. Under mild hypotheses, this code is spherical 2-design, which yields upper bound on its covering radius on the sphere.This bound, in turn, gives an upper bound on the covering radius of the Hadamard codes. 

Joint work with Minjia Shi, Danni Lu, A. Armario, R. Egan, F. Ozbudak.