Search results for "Combinatorics"
showing 10 items of 1770 documents
On parameterized complexity to determine b-chromatic and partial Grundy numbers
2014
International audience
Gray code for compositions of n with parts 1 and p
2009
International audience
ECO-generation for some restricted classes of compositions
2013
International audience; We study several restricted classes of compositions by giving one-to-one maps between them and different classes of restricted binary strings or pattern avoiding permutations. Inspired by the ECO method, new succession rules for these classes are presented. Finally, we obtain generating algorithms in Constant Amortized Time (CAT) for theses classes.
Etudes d'objets combinatoires : applications à la bio-informatique
2011
This thesis considers classes of combinatorial objects that model data in bioinformatics. We have studied two methods of mutation of genes within the genome : duplication and inversion. At first,we study the problem of the whole mirror duplication-random lossmodel in terms of pattern avoiding permutations. We prove that the class of permutations obtained with this method after p duplications from the identity is the class of permutations avoiding alternating permutations of length 2p + 1.We also enumerate the number of duplications that are necessary and sufficient to obtain any permutation of length n from the identity. We also suggest two efficient algorithms to reconstruct two different …
Si j'aurai su, j'aurai pas venu" : éclairage stratégique sur le lancement simultané des deux " Guerre des Boutons "
2014
“If I knew, I will not come”: strategic insight on the simultaneous launch of the two Guerre des BoutonsThe purpose of this paper is to propose an insight on an unusual strategic situation in the movie industry: thesimultaneous launch on screens of two almost identical movies, La Guerre des Boutons. After recalling the stakesattached to the product launch in the film industry, a monograph devoted to this direct confrontation, supplementedby an analysis of the critics of spectators, is proposed. This analysis reveals determinants (the conflictand lack of control in the film industry) and consequences (sub-optimal strategy) of the temporal agglomeration.
On the tensor degree of finite groups
2013
We study the number of elements $x$ and $y$ of a finite group $G$ such that $x \otimes y= 1_{_{G \otimes G}}$ in the nonabelian tensor square $G \otimes G$ of $G$. This number, divided by $|G|^2$, is called the tensor degree of $G$ and has connection with the exterior degree, introduced few years ago in [P. Niroomand and R. Rezaei, On the exterior degree of finite groups, Comm. Algebra 39 (2011), 335--343]. The analysis of upper and lower bounds of the tensor degree allows us to find interesting structural restrictions for the whole group.
Una política juvenil para promover el desarrollo local: un estudio de caso
2019
El artículo presenta un estudio de caso de una política juvenil realizada en la última década en una región del Sur de Italia. Su interés reside en la versatilidad, el enfoque multidimensional y en el hecho de haber actuado como un óptimo instrumento de desarrollo local. El estudio de caso se ha realizado a través del análisis documental de las evaluaciones ex -ante, durante y ex – post que se hicieron para valorar el impacto de la política. La reflexión que el caso propone se enfoca en cómo se puede promover eficazmente el desarrollo local a través de políticas más trasversales.
On the Influence of Grammars on Crossover in Grammatical Evolution
2021
Standard grammatical evolution (GE) uses a one-point crossover (“ripple crossover”) that exchanges codons between two genotypes. The two resulting genotypes are then mapped to their respective phenotypes using a Backus-Naur form grammar. This article studies how different types of grammars affect the resulting individuals of a ripple crossover. We distinguish different grammars based on the expected number of non-terminals chosen when mapping genotype codons to phenotypes, \(B_{avg}\). The grammars only differ in \(B_{avg}\) but can express the same phenotypes. We perform crossover operations on the genotypes and find that grammars with \(B_{avg} > 1\) lead to high numbers of either very sm…
On the suffix automaton with mismatches
2007
International audience; In this paper we focus on the construction of the minimal deterministic finite automaton S_k that recognizes the set of suffixes of a word w up to k errors. We present an algorithm that makes use of S_k in order to accept in an efficient way the language of all suffixes of w up to k errors in every window of size r, where r is the value of the repetition index of w. Moreover, we give some experimental results on some well-known words, like prefixes of Fibonacci and Thue-Morse words, and we make a conjecture on the size of the suffix automaton with mismatches.
Optimal recovery of a radiating source with multiple frequencies along one line
2020
We study an inverse problem where an unknown radiating source is observed with collimated detectors along a single line and the medium has a known attenuation. The research is motivated by applications in SPECT and beam hardening. If measurements are carried out with frequencies ranging in an open set, we show that the source density is uniquely determined by these measurements up to averaging over levelsets of the integrated attenuation. This leads to a generalized Laplace transform. We also discuss some numerical approaches and demonstrate the results with several examples.