On the simplest centralizer of a language

Given a finite alphabet Σ and a language L ⊆ ∑+, the centralizer of L is defined as the maximal language commuting with it. We prove that if the primitive root of the smallest word of L (with respect to a lexicographic order) is prefix distinguishable in L then the centralizer of L is as simple as possible, that is, the submonoid L*. This lets us obtain a simple proof of a known result concerning the centralizer of nonperiodic three-word languages

Asymptotics of Z-convex polyominoes

The degree of convexity of a convex polyomino P is the smallest integer k such that any two cells of P can be joined by a monotone path inside P with at most k changes of direction. In this paper we show that one can compute in polynomial time the number of polyominoes of area n and degree of convexity at most 2 (the so-called Z-convex polyominoes). The integer sequence that we have computed allows us to conjecture the asymptotic number an of Z-convex polyominoes of area n, ɑn ∼ C·exp(π)√11n/4⁄n3/2

On computing the degree of convexity of polyominoes

In this paper we present an algorithm which has as input a convex polyomino P and computes its degree of convexity, de\ufb01ned as the smallest integer k such that any two cells of P can be joined by a monotone path inside P with at most k changes of direction. The algorithm uses space O(m + n) to represent a polyomino P with n rows and m columns, and has time complexity O(min(m, rk)), where r is the number of corners of P. Moreover, the algorithm leads naturally to a decomposition of P into simpler polyominoes

Améliorations sur le système d’observation du bassin de la Rivière Sirba pour la gestion des risques naturels

Updating of the rating curves and of the historical series of Garbey Kourou (Sirba river - Niger

Analysis of shared common genetic risk between amyotrophic lateral sclerosis and epilepsy

Because hyper-excitability has been shown to be a shared pathophysiological mechanism, we used the latest and largest genome-wide studies in amyotrophic lateral sclerosis (n = 36,052) and epilepsy (n = 38,349) to determine genetic overlap between these conditions. First, we showed no significant genetic correlation, also when binned on minor allele frequency. Second, we confirmed the absence of polygenic overlap using genomic risk score analysis. Finally, we did not identify pleiotropic variants in meta-analyses of the 2 diseases. Our findings indicate that amyotrophic lateral sclerosis and epilepsy do not share common genetic risk, showing that hyper-excitability in both disorders has distinct origins

On the Generation of Convex Polyominoes

A convex polyomino can be easily represented by a pair of suitable integer vectors. This lets us design a CAT (Constant Amortized Time) algorithm for generating all convex polyominoes of size n using O(n) space