Bernt Lindström

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A B2-sequence is a sequence a1 < a2 < · · · < ar of positive integers such that the sums ai + aj , 1 ≤ i ≤ j ≤ r, are different. When q is a power of a prime and θ is a primitive element in GF (q2) then there are B2-sequences A(q, θ) of size q with aq < q2, which were discovered by R. C. Bose and S. Chowla. In Theorem 2.1 I will give a faster alternative to(More)
Proof. The proof depends on the existence of pairs of orthogonal latin squares of order n = 0 (mod 3), except for n = 6 (see [2, Theorem 13.4.1]). We prove that the lines of K 6 , can be colored in 3r colors such that no subgraph Pl is uni-colored. We write K 6 , as a join of three copies of K2,. We use induction on the exponent of the largest power of 3(More)
The strong join of two geometries G and H relative to a common subgeometry is a geometry on the point set (G x) u (H x) w x, the closed sets k of which have the property that k n G is closed in the geometry G and k n His closed in the geometry H. The strong join does not always exist, but if x is a modular flat of G (or H) it does exist. This was proved by(More)