Publications [#236012] of Robert Calderbank

Journal articles or Book chapters PUBLISHED

1. Brouwer, AE; Calderbank, AR, An Erdös-Ko-Rado theorem for regular intersecting families of octads, Graphs and Combinatorics, vol. 2 no. 1 (December, 1986), pp. 309-316, Springer Nature, ISSN 0911-0119 [doi]
   (last updated on 2026/01/17)

   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.