A characterization of some {3v2 + v3, 3v1 + v2; 3, 3}-minihypers and some [15, 4, 9; 3]-codes with B2 = 0

It is known (cf. Hill and Newton (Ars Combin., 25A (1988), 61–72; Designs Codes Cryptography, 2 (1992), 137–157) and Remark A.2 in the Appendix) that (1) there is no [14, 4, 9; 3]-code meeting the Griesmer bound and (2) if C is a [15, 4, 9; 3]-code then B₂ = 0 or 2 and (3) there is a one-to-one correspondence between the set of all nonequivalent [15, 4, 9; 3]-codes with B₂ = 0 and the set of all {3v₂ + v₃, 3v₁ + v₂: 3, 3}-minihypers, where v₁ = 1, v₂ = 4, v₃ = 13 and B₂ denotes the number of codewords of weight 2 in its dual code. Recently it has been shown by Eupen and Hill (Designs Codes Cryptography, 4 (1994) 271–282) that a [15, 4, 9; 3]-code with B₂ = 2 is unique up to equivalence. The purpose of this paper is to characterize all [15, 4, 9; 3]-codes with B₂ = 0 using the geometrical structure of the corresponding {3v₂ + v₃, 3v₁ + v₂; 3, 3}-minihypers. Those results give a complete characterization of [15, 4, 9; 3]-codes.