Author/Authors :
Masaaki Harada، نويسنده , , Michio Ozeki، نويسنده ,
Abstract :
In this note, an extremal doubly-even [40,20,8] code with covering radius 7 is given. This code is the first extremal doubly-even code whose covering radius does not meet the Delsarte bound. Extremal singly-even codes with the smallest covering radius are also given. One of them is an extremal singly-even [44,22,8] code with covering radius 7, which determines t[43,22]=6 by puncturing.
