Abstract:
Codewords of weight 8 in the [24, 12] binary Golay code are called octads. A family ℱ of octads is said to be a regular intersecting family if ℱ is a 1-design and |x ∩ y| ≠ 0 for all x, y ∈ ℱ. We prove that if ℱ is a regular intersecting family of octads then |ℱ| ≤ 69. Equality holds if and only if ℱ is a quasi-symmetric 2-(24, 8, 7) design. We then apply techniques from coding theory to prove nonexistence of this extremal configuration. © 1986 Springer-Verlag.