منابع مشابه
Homogeneous Permutations
There are just five Fraı̈ssé classes of permutations (apart from the trivial class of permutations of a singleton set); these are the identity permutations, reversing permutations, composites (in either order) of these two classes, and all permutations. The paper also discusses infinite generalisations of permutations, and the connection with Fraı̈ssé’s theory of countable homogeneous structures,...
متن کاملSome t-Homogeneous Sets of Permutations
Perpendicular Arrays are ordered combinatorial structures, which recently have found applications in cryptography. A fundamental construction uses as ingredients combinatorial designs and uniformly t-homogeneous sets of permutations. We study the latter type of objects. These may also be viewed as generalizations of t-homogeneous groups of permutations. Several construction techniques are given...
متن کاملFinite Homomorphism-Homogeneous Permutations via Edge Colourings of Chains
A relational structure is homomorphism-homogeneous if any homomorphism between its finite substructures extends to an endomorphism of the structure in question. In this note, we characterise all permutations on a finite set enjoying this property. To accomplish this, we switch from the more traditional view of a permutation as a set endowed with two linear orders to a different representation b...
متن کاملA Stream Cipher Based on Chaotic Permutations
In this paper we introduce a word-based stream cipher consisting of a chaotic part operating as a chaotic permutation and a linear part, both of which designed on a finite field. We will show that this system can operate in both synchronized and self-synchronized modes. More specifically, we show that in the self-synchronized mode the stream cipher has a receiver operating as an unknown input o...
متن کاملIntersecting families of permutations and partial permutations
The above result motivated the study of intersecting families of permutations which was initiated by Deza and Frankl, see [2]. Let Sn be the symmetric group on [n], that is the group of all permutations of [n]. For a positive integer t, a subset A of Sn is said to be t-intersecting if, for any g, h ∈ A with g 6= h, we have |{x : g(x) = h(x)}| ≥ t. By an intersecting family, we mean an 1-interse...
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ژورنال
عنوان ژورنال: The Electronic Journal of Combinatorics
سال: 2002
ISSN: 1077-8926
DOI: 10.37236/1674