Transversals for association schemes
نویسندگان
چکیده
منابع مشابه
Clifford Theory for Association Schemes
Clifford theory of finite groups is generalized to association schemes. It shows a relation between irreducible complex characters of a scheme and a strongly normal closed subset of the scheme. The restriction of an irreducible character of a scheme to a strongly normal closed subset coniatns conjugate characters with same multiplicities. Moreover some strong relations are obtained.
متن کاملDeduction Schemes for Association Rules
Several notions of redundancy exist for Association Rules. Often, these notions take the form “any dataset in which this first rule holds must obey also that second rule, therefore the second is redundant”; if we see datasets as interpretations (or models) in the logical sense, this is a form of logical entailment. In many logics, entailment has a syntactic counterpart in the form of a deductio...
متن کاملCommon Transversals
Given t families, each family consisting of s finite sets, we show that if the families “separate points" in a natural way, and if the union of all the sets in all the families contains more than (s+1)t st 1 1 elements, then a common transversal of the t families exists. In case each family is a covering family, the bound is st st 1. Both of these bounds are best possible. This work extends rec...
متن کاملConvex Transversals
We answer the question initially posed by Arik Tamir at the Fourth NYU Computational Geometry Day (March, 1987): “Given a collection of compact sets, can one decide in polynomial time whether there exists a convex body whose boundary intersects every set in the collection?” We prove that when the sets are segments in the plane, deciding existence of the convex stabber is NP-hard. The problem re...
متن کاملIntroduction to Association Schemes
The present paper gives an introduction to the theory of association schemes, following Bose-Mesner (1959), Biggs (1974), Delsarte (1973), Bannai-Ito (1984) and Brouwer-Cohen-Neumaier (1989). Apart from definitions and many examples, also several proofs and some problems are included. The paragraphs have the following titles:
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of the Mathematical Society of Japan
سال: 2000
ISSN: 0025-5645
DOI: 10.2969/jmsj/05220465