(1) Department of Mathematics, Beijing Jiaotong University, Beijing, 100044, P.R. China
Abstract:
A directed balanced incomplete block design (or DB(k,;v)) (X,) is called self-converse if there is an isomorphic mapping f from (X,) to (X,–1), where –1={B–1:B} and B–1=(xk,xk–1,,x2,x1) for B=(x1,x2,,xk–1,xk). In this paper, we give the existence spectrum for self-converse DB(4,1;v).AMS Classification:05BResearch supported in part by NSFC Grant 10071002 and SRFDP under No. 20010004001
;v)) (X,
) is called self-converse if there is an isomorphic mapping f from (X,
,x 2,x 1) for B=(x 1,x 2,
05BResearch supported in part by NSFC Grant 10071002 and SRFDP under No. 20010004001