A univariate polynomial f over a field is decomposable if it is the composition f = g ◦h of two polynomials g and h whose degree is at least 2. We determine an approximation to the number of decomposable polynomials over a finite field. The tame case, where the field characteristic p does not divide the degree n of f , is reasonably well understood, and we obtain exponentially decreasing error ...

A univariate polynomial f over a field is decomposable if it is the composition f = g ◦h of two polynomials g and h whose degree is at least 2. We determine an approximation to the number of decomposable polynomials over a finite field. The tame case, where the field characteristic p does not divide the degree n of f , is reasonably well understood, and we obtain exponentially decreasing error ...

A graph G of order n is called arbitrarily vertex decomposable if for each sequence (a1, . . . , ak) of positive integers such that a1+. . .+ak = n there exists a partition (V1, . . . , Vk) of the vertex set of G such that for each i ∈ {1, . . . , k}, Vi induces a connected subgraph of G on ai vertices. D. Barth and H. Fournier showed that if a tree T is arbitrarily vertex decomposable, then T ...

The recursive method formalized by Nijenhuis and Wilf [15] and systematized by Flajolet, Van Cutsem and Zimmermann [8], is extended here to oating-point arithmetic. The resulting ADZ method enables one to generate decomposable data structures | both labelled or unlabelled | uniformly at random, in expected O(n ) time and space, after a preprocessing phase of O(n ) time, which reduces to O(n ) f...

Given N a non generic smooth CR submanifold of C, N = {(N, h(N))} where N is generic in C and h is a CR map from N into C. We prove, using only elementary tools, that if h is decomposable at p′ ∈ N then any decomposable CR distribution on N at p = (p′, h(p′)) extends holomorphically to a complex transversal wedge. This gives an elementary proof of the well known equivalent for totally real non ...

In such areas as knowledge discovery, data mining and logical analysis of data, methodologies to 0nd relations among attributes are considered important. In this paper, given a data set (T; F) where T ⊆ {0; 1}n denotes a set of positive examples and F ⊆ {0; 1}n denotes a set of negative examples, we propose a method to identify decomposable structures among the attributes of the data. We 0rst s...

A class of n-ary Poisson structures of constant rank is indicated. Then, one proves that the ternary Poisson brackets are exactly those which are deened by a decomposable 3-vector eld. The key point is the proof of a lemma which tells that an n-vector (n 3) is decomposable ii all its contractions with up to n ? 2 covectors are decomposable. In the last years, several authors have studied genera...

A class of n-ary Poisson structures of constant rank is indicated. Then, one proves that the ternary Poisson brackets are exactly those which are deened by a decomposable 3-vector eld. The key point is the proof of a lemma which tells that an n-vector (n 3) is decomposable ii all its contractions with up to n ? 2 covectors are decomposable. In the last years, several authors have studied genera...

A graph G of order n is said to be arbitrarily vertex decomposable if for each sequence (n1, . . . , nk) of positive integers such that n1 + · · · + nk = n there exists a partition (V1, . . . , Vk) of the vertex set of G such that for each i ∈ {1, . . . , k}, Vi induces a connected subgraph of G on ni vertices. The main result of the paper reads as follows. Suppose that G is a connected graph o...

Let n, r be integers with 0 ≤ r ≤ n− 1. An n×n matrix A is called r-partly decomposable if it contains a k×l zero submatrix with k+l = n−r+1. A matrix which is not r-partly decomposable is called r-indecomposable (shortly, r-inde). Let Eij be the n × n matrix with a 1 in the (i, j) position and 0’s elsewhere. If A is r-indecomposable and, for each aij 6= 0, the matrix ∗Research supported by Nat...