On an Assmus–Mattson type theorem for type I and even formally self‐dual codes
Tsuyoshi Miezaki, Hiroyuki Nakasora · Journal of Combinatorial Designs · 2023
Abstract In the present paper, we give an Assmus–Mattson type theorem for near‐extremal Type I and even formally self‐dual codes. We show the existence of 1‐designs or 2‐designs for these codes. As a corollary, we prove the uniqueness of a self‐orthogonal 2‐ design.