Tuyển tập các báo cáo nghiên cứu khoa học về toán học trên tạp chí toán học quốc tế đề tài: New regular partial diﬀerence sets and strongly regular graphs with parameters (96,20,4,4) and (96,19,2,4)...
Combinatorics is generally concerned with counting arrangements
within a finite set. One of the basic problems is to determine the
number of possible configurations of a given kind. Even when the
rules specifying the configuration are relatively simple, the questions
of existence and enumeration often present great difficulties. Besides
counting, combinatorics is also concerned with questions involving
symmetries, regularity properties, and morphisms of these
arrangements. The theory of block designs is an important area where
these facts are very apparent.