Preparata code: Difference between revisions

Content deleted Content added
m changed stub type to crypto
Line 2:
 
==Construction==
Let ''m'' be an odd number, and ''<math>n'' = 2<sup>''^m''-1</supmath>&nbsp;&minus;&nbsp;1. We first describe the '''extended Preparata code''' of length 2''n''&nbsp;<math>2n+&nbsp;2 = 2<sup>''^{m''&nbsp;+&nbsp;1}</supmath>: the Preparata code is then derived by deleting one position. The words of the extended code are regarded as pairs (''X'',&nbsp;''Y'') of 2<sup>''m''</sup>-tuples, each corresponding to subsets of the [[finite field]] GF(2<sup>''m''</sup>) in some fixed way.
 
The extended code contains the words (''X'',&nbsp;''Y'') satisfying three conditions