Codes and Expansions (CodEx) Seminar

Kiyoto Yoshino (Tohoku University)
The Lemmens-Seidel conjecture for base size 5

In 1973, Lemmens and Seidel raised the so-called Lemmens-Seidel conjecture. In order to prove it, we need to show it for base sizes 3,4,5 and 6. In 2020, Lin and Yu proved the conjecture for base size 3 with a computer, and claimed to prove it for base size 5. However, there is a gap. In 2022, Cao, Koolen, Lin and Yu proved the conjecture for base sizes 3 and 4 without a computer. In this talk, I show the conjecture for base size 5.