Word and tree codes are studied in a common framework, that of polypodes which are sets endowed with a substitution like operation. Many examples are given and basic properties are examined. The code decomposition theorem is valid in this general setup.

Word and tree codes are studied in a common framework, that of polypodes which are sets endowed with a substitution like operation. Many examples are given and basic properties are examined. The code decomposition theorem is valid in this general setup.

We consider Weil sums of binomials of the form $W_{F,d}\left(a\right)={\sum }_{x\in F}\psi (x^d-ax)$, where F is a finite field, ψ: F → ℂ is the canonical additive character, $gcd(d,|F^{\times }\left|\right)=1$, and $a\in F^{\times }$. If we fix F and d, and examine the values of $W_{F,d}\left(a\right)$ as a runs through $F^{\times }$, we always obtain at least three distinct values unless d is degenerate (a power of the characteristic of F modulo $|F^{\times }|$). Choices of F and d for which we obtain only three values are quite rare and desirable in a wide variety of applications. We show that if F is a field of order 3ⁿ with n odd, and $d=3^r+2$ with...

We show that there are well separated families of quantum expanders with asymptotically the maximal cardinality allowed by a known upper bound. This has applications to the “growth" of certain operator spaces: It implies asymptotically sharp estimates for the growth of the multiplicity of $M_N$-spaces needed to represent (up to a constant $C>1$) the $M_N$-version of the $n$-dimensional operator Hilbert space $O{H}_n$ as a direct sum of copies of $M_N$. We show that, when $C$ is close to 1, this multiplicity grows as $exp\beta n{N}^2$ for...

In this paper we compute some bounds of the Balaban index and then by means of group action we compute the Balaban index of vertex transitive graphs. ACM Computing Classification System (1998): G.2.2 , F.2.2.

A generalized-theta-graph is a graph consisting of a pair of end vertices joined by k (k ≥ 3) internally disjoint paths. We denote the family of all the n-vertex generalized-theta-graphs with k paths between end vertices by Θⁿₖ. In this paper, we determine the sharp lower bound and the sharp upper bound for the total number of matchings of generalized-theta-graphs in Θⁿₖ. In addition, we characterize the graphs in this class of graphs with respect to the mentioned bounds.

En este artículo se construye un cono convexo sobre un grafo y se estudian las propiedades básicas de este cono convexo: dimensión, linealidad y sistemas minimales de generadores. El interés de esta situación tiene su origen en problemas de decisión, donde la información disponible está dada por órdenes parciales entre las componentes de la información. Sin embargo, el estudio realizado es independiente de los problemas de decisión que lo motivan.

This article, one of a series, approaches the topics of marriage and kinship through a revitalized kinetic structural approach that shifts the primary focus from abstract models of rules, terminologies, attitudes and norms to exploration of concrete relations in a population, analyzed graph-theoretically in their full complexity as networks. Network representation using the graphe de parenté (see below) serves as the basis for examining marriage alliance theory, population structure (such as endogamy...

Soit $p_k$ le $k$-ième nombre premier. Une fonction arithmétique complètement additive est définie sur ${\mathbb{N}}^{*}$ par la donnée des $f\left(p_k\right)$ et la formule $f\left(n\right)={\sum }_{k\ge 1}f(p_k)v_{p_k}\left(n\right)$$(n\ge 1)$, où $v_p$ désigne la...