In this paper we will deal with the balance properties of the infinite binary words associated to β-integers when β is a quadratic simple Pisot number. Those words are the fixed points of the morphisms of the type $\varphi \left(A\right)=A^{p}B$, $\varphi \left(B\right)=A^q$ for $p\in \mathbb{N}$, $q\in \mathbb{N}$, $p\ge q$, where $\beta =\frac{p+\sqrt{p^2+4q}}{2}$. We will prove that such word is t-balanced with $t=1+\left[(p-1)/(p+1-q)\right]$. Finally, in the case that p < q it is known [B. Adamczewski, Theoret. Comput. Sci.273 (2002) 197–224] that the fixed point of the substitution $\varphi \left(A\right)=A^{p}B$, $\varphi \left(B\right)=A^q$ is not m-balanced for any m. We exhibit an infinite sequence...

Suppose a graph G = (V,E) with edge weights w(e) and edges partitioned into disjoint categories S₁,...,Sₚ is given. We consider optimization problems on G defined by a family of feasible sets (G) and the following objective function: $L₅\left(D\right)=ma{x}_{1\le i\le p}(ma{x}_{e\in S_i\cap D}w\left(e\right)-mi{n}_{e\in S_i\cap D}w\left(e\right))$ For an arbitrary number of categories we show that the L₅-perfect matching, L₅-a-b path, L₅-spanning tree problems and L₅-Hamilton cycle (on a Halin graph) problem are NP-complete. We also summarize polynomiality results concerning above objective functions for arbitrary...

A word u defined over an alphabet $𝒜$ is c-balanced (c∈$\mathbb{N}$) if for all pairs of factors v, w of u of the same length and for all letters a∈$𝒜$, the difference between the number of letters a in v and w is less or equal to c. In this paper we consider a ternary alphabet $𝒜$ = {L, S, M} and a class of substitutions ${\varphi }_p$ defined by ${\varphi }_p$(L) = LpS, ${\varphi }_p$(S) = M, ${\varphi }_p$(M) = Lp–1S where p> 1. We prove that the fixed point of ${\varphi }_p$, formally written as ${\varphi }_p^{\infty }$(L), is 3-balanced and that its Abelian complexity is bounded above by...

A single-machine batch scheduling problem is investigated. Each job has a positive processing time and due-date. Setup times are assumed to be identical for all batches. All batch sizes cannot exceed a common upper bound. As in many practical situations, jobs have to be subject to flexible precedence constraints. The aim of this paper is to find an optimal batch sequence. The sequence is to minimize the maximal completion time and maximize the minimum value of desirability of the fuzzy precedence....

Probabilistic mixtures provide flexible “universal” approximation of probability density functions. Their wide use is enabled by the availability of a range of efficient estimation algorithms. Among them, quasi-Bayesian estimation plays a prominent role as it runs “naturally” in one-pass mode. This is important in on-line applications and/or extensive databases. It even copes with dynamic nature of components forming the mixture. However, the quasi-Bayesian estimation relies on mixing via constant...

We carry out Bayesian inference for the Jelinski-Moranda and Littlewood software failure models given a sample of failure times. Furthermore, we illustrate how to assess the optimal length of an additional pre-release testing period under each of these models. Modern Bayesian computational methods are used to estimate the posterior expected utility of testing for and additional time.

We present bdim (Bibliteca Digitale Italiana di Matematica) the Italian project of math digitization. The project has been started by SIMAI (Società Italiana di Matematica Applicata e Industriale) and UMI (Unione Matematica Italiana) with initial support from the Biblioteca Digitale Italiana and the Italian Ministry of Beni and Attività Culturali and with the help of Numdam. At the moment bdim consists of approximately 1,300 articles, 11,000 pages (articles from Bollettino Unione Matematica Italiana,...