5 papers
Nonexistence Results and Constructions for Signed Difference Sets
Zhiwen He, Jiayan Wu
Signed difference sets (SDSs) extend ordinary difference sets by allowing negative coefficients. We establish new nonexistence criteria and existence constructions for SDSs in fini…
On central difference sets in Suzuki -groups of type
Wendi Di, Zhiwen He
In this paper, when the order of is even, we prove that there exists no central difference sets in and establish some non-existence results of central partial differ…
Linear Codes Of 2-Designs As Subcodes Of The Extended Generalized Reed-Muller Codes
Zhiwen He, Jiejing Wen
This paper is concerned with the affine-invariant ternary codes which are defined by Hermitian functions. We compute the incidence matrices of 2-designs that are supported by the m…
Two Kinds of Constructions of Directed Strongly Regular Graphs from Partial Sum Families and Semi-direct Products of Groups
Jingkun Zhou, Zhiwen He, Zhao Chai
In this paper, we construct directed strongly regular graphs with new parameters by using partial sum families with local rings. 16 families of new directed strongly regular graphs…
Partial difference sets and amorphic Cayley schemes in non-abelian -groups
Tao Feng, Zhiwen He, Yu Qing Chen
In this paper, we consider regular automorphism groups of graphs in the RT family and the Davis-Xiang family and amorphic abelian Cayley schemes from these graphs. We derive gen…