吴文俊数学重点实验室组合图论系列讲座之三十八【Etsuko Bannai】

题  目：Diameter perfect codes and β(i) designs.

报告人：Etsuko Bannai [教授]  Kyushu University

时  间：2014年5月4日    上午11：00—12：00

地  点：东区管理科研楼 数学科学学院1216室

摘  要：

Diameter perfect code is a concept de_ned for distance regular graphs in the paper by Ahlswede-Aydinian-Khachatrian (2001). On the other hand _(i) design is a concept de_ned for Johnson graphs J(v; k) by Noda (2001). Recently we found that diameter perfect codes in Johnson graphs and _(i) designs are equivalent concepts. We obtained upper bound and lower bound of v for which a _(i) design exists. We apply this bound to the problem of of the perfect e-codes in J(v; k) and improved the bound given by Roos in 1983. This is joint work with Ryuzaburo Noda. For the details, see arXiv:1404.3821.

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