let be a set and let be the set of subsets of . the pair in which is a collection of elements of (blocks) is called a design if every element of appears in , times. is called a symmetric design if . in a symmetric design, each element of appears times in blocks of . a mapping between two designs and is an isomorphism if is a one-to-one correspondence and . every isomorphism of a design, , to it...

the main aim of this article is to study (v,k,λ)-symmetric designs admitting a flag-transitive and point-primitive automorphism group g whose socle is psl(3,q). we indeed show that the only possible design satisfying these conditions is a desarguesian projective plane pg(2,q) and g > psl(3,q).

let d be a symmetric 2-(121, 16, 2) design with the automorphism group of aut(d). in this paper the order of automorphism of prime order of aut(d) is studied, and some results are obtained about the number of fixed points of these automorphisms. also we will show that |aut(d)|=2p 3q 5r 7s 11t 13u, where p, q, r, s, t and u are non-negative integers such that r, s, t, u ? 1. in addition we prese...

This paper presents arguments supporting the thesis that clusters of SMPs interconnected with general purpose networks (perhaps several different networks to support both low-latency and bulk data transfers) are the architecture that will provide scalable high-performance computing environments. The paper presents an analysis of the high performance computing environment based on the state of t...

Let D be a symmetric 2-(121, 16, 2) design with the automorphism group of Aut(D). In this paper the order of automorphism of prime order of Aut(D) is studied, and some results are obtained about the number of fixed points of these automorphisms. Also we will show that |Aut(D)|=2p 3q 5r 7s 11t 13u, where p, q, r, s, t and u are non-negative integers such that r, s, t, u ? 1. In addition we prese...

we investigate buchbaum and eisenbud's construction of the second symmetric power $s_r(x)$ of a chain complex $x$ of modules over a commutative ring $r$. we state and prove a number of results from the folklore of the subject for which we know of no good direct references. we also provide several explicit computations and examples. we use this construction to prove the following ...

let $g$ be an automorphism group of a‎ ‎$2$-$(v,k,4)$ symmetric design $mathcal d$‎. ‎in this paper‎, ‎we‎ ‎prove that if $g$ is flag-transitive point-primitive‎, ‎then the‎ ‎socle of $g$ cannot be an exceptional group of lie type‎.

E-optimality is studied for three treatments in an arbitrary n-way heterogeneity setting. In some cases maximal trace designs cannot be E-optimal. When there is more than one E-optimal design for a given setting, the best with respect to all reasonable criteria is determined.