منابع مشابه
Non-symmetric 2-Designs Modulo 2
Necessary conditions are obtained for the existence of a 2 (v, k, X) design, for which the block intersection sizes sl, s2, . 9 sn satisfy sl ---s2 . , . --s n =s (mod 2e), where e is odd. These conditions are obtained by combining restrictions on the Smith Normal Form of the incidence matrix of the design with some well known properties of self-orthogonal binary codes with all weights divisibl...
متن کاملClassification of 2-transitive symmetric designs
All symmetric designs are determined for which the automorphism group is 2-transitive on the set of points. This note contains a proof of the following result. Theorem. Let D be a symmetric design with v > 2k such that Aut D is 2-transitive on points. Then D is one o f the following: (i) a projective space; (ii) the unique Hadamard design with v = I 1 and k = 5; (iii) a unique design with v = 1...
متن کاملConstruction of a Class of Quasi-Symmetric 2-Designs
In this article we study proper quasi-symmetric 2 − designs i.e. block designs having two intersection numbers and , where 0 < < . Also, we present a construction method for quasi-symmetric 2 − designs with block intersection numbers and + 1, where is a prime number, under certain conditions on the cardinality of point set.
متن کاملFlag-transitive non-symmetric 2-designs with (r, λ) = 1 and alternating socle
This paper deals with flag-transitive non-symmetric 2-designs with (r, λ) = 1. We prove that if D is a non-trivial non-symmetric 2-(v, k, λ) design with (r, λ) = 1 and G 6 Aut(D) is flag-transitive with Soc(G) = An for n > 5, then D is a 2-(6, 3, 2) design, the projective space PG(3, 2), or a 2-(10, 6, 5) design.
متن کاملEuler Numbers modulo 2
Let {En} be the Euler numbers. In the paper we give a general congruence modulo 2(m+2)n involving for Eb and for E2mk+b, where k, m, n are positive integers and b ∈ {0, 2, 4, . . .}. MSC: Primary 11B68, Secondary 11A07
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ژورنال
عنوان ژورنال: Designs, Codes and Cryptography
سال: 1993
ISSN: 0925-1022,1573-7586
DOI: 10.1007/bf01389355