中文摘要：

为了使Chase型译码算法的纠错半径尽可能大，根据l-defeasible集合的定义以及它的一些判别条件，通过寻找覆盖所有长度为2l＋2的向量所需半径为l的球的球心向量，构造出了l-defeasible集合，即Chase型译码算法的搜索中心。

英文摘要：

To maximize the squared error-correction radius （SECR） of a Chase-like decoding algorithm, the constructions for the l-defeasible set were given according to the definition of the l-defeasibleset and some decision conditions, by investigating the center vectors of spheres of radius l which cover all the vectors of length 2l ＋ 2, namely the search centers of Chase-like decoding algorithms.