Quasi-symmetric designs related to the triangular graph
نویسندگان
چکیده
منابع مشابه
Conditions for the Parameters of the Block Graph of Quasi-Symmetric Designs
A quasi-symmetric design (QSD) is a 2-(v, k, λ) design with intersection numbers x and y with x < y. The block graph of such a design is formed on its blocks with two distinct blocks being adjacent if they intersect in y points. It is well known that the block graph of a QSD is a strongly regular graph (SRG) with parameters (b, a, c, d) with smallest eigenvalue −m = −k−x y−x . The classificatio...
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obtain a new for the of a-(u, A) design the block intersection designs are eliminated by an ad hoc coding theoretic argument. A 2-(v, k, A) design 93 is said to be quasi-symmetric if there are two block intersection sizes s1 and s2. The parameters of the complementary design !3* are related to the parameters of 93 as follows: Here Ai denotes the number of blocks through a given i points (and A ...
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A quasi-symmetric design is a (v, k, λ) design with two intersection numbers x, y where 0 ≤ x < y < k. We show that for fixed x, y, λ with x > 1, λ > 1, y = λ and λ (4xy + ((y − x) − 2x− 2y + 1)λ) a perfect square of a positive integer, there exist finitely many quasi-symmetric designs. We rule out the possibilities of quasi-symmetric designs corresponding to y = x + 3 and (λ, x) = (9, 2), (8, ...
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ژورنال
عنوان ژورنال: Designs, Codes and Cryptography
سال: 1995
ISSN: 0925-1022,1573-7586
DOI: 10.1007/bf01388502