Woo Sun Lee (Pohang University of Science and Technology, Korea) - Arithmetic Completely Regular Codes

Mathematics - Colloquium

Friday, January 22, 2010
11:00 AM-12:00 PM

Stratton Hall
203

ABSTRACT: Completely regular codes were introduced by Delsarte in 1973.
Completely regular codes can be seen as a generalization of perfect codes, as all perfect codes are completely regular, and one of the main tools for studying perfect codes, namely Lloyd's theorem, still holds for completely regular codes.
In this talk, we study cartesian products of completely regular codes in Hamming graphs. This leads us to study of completely regular codes whose eigenvalues are in arithmetic progression. We will determine exactly when the product of two completely regular codes in two Hamming graphs is completely regular. We will also present the theory of completely regular codes in the Hamming graph enjoying the property that eigenvalues of the code are in arithmetic progression and give full classification of the case of linear completely regular codes with eigenvalues which are in arithmetic progression. (This is joint work with J.H. Koolen and W.J. Martin.)

Suggested Audiences: Adult, College

E-mail: ma-chair@wpi.edu

Last Modified: January 15, 2010 at 10:36 AM

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