Search results for "Integer"
showing 10 items of 250 documents
Chromatic sums for colorings avoiding monochromatic subgraphs
2015
Abstract Given graphs G and H, a vertex coloring c : V ( G ) → N is an H-free coloring of G if no color class contains a subgraph isomorphic to H. The H-free chromatic number of G, χ ( H , G ) , is the minimum number of colors in an H-free coloring of G. The H-free chromatic sum of G , Σ ( H , G ) , is the minimum value achieved by summing the vertex colors of each H-free coloring of G. We provide a general bound for Σ ( H , G ) , discuss the computational complexity of finding this parameter for different choices of H, and prove an exact formulas for some graphs G. For every integer k and for every graph H, we construct families of graphs, G k with the property that k more colors than χ ( …
Witt vectors and Fermat quotients
2008
Abstract We give a representation of any integer as a vector of the Witt ring W ( Z p ) and relate it to the Fermat quotient q ( n ) = ( n p − 1 − 1 ) / p . Logarithms are introduced in order to establish an isomorphism between the commutative unipotent groups 1 + p W ( Z p ) and W ( Z p ) .
Conway irreducible hyperbolic knots with two common covers
2005
International audience; For each pair of coprime integers n > m ≥ 2 we construct pairs of non equivalent Conway irreducible hyperbolic knots with the same n-fold and m-fold cyclic branched covers.
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 …
The mKdV equation and multi-parameters rational solutions
2021
Abstract N -order solutions to the modified Korteweg–de Vries (mKdV) equation are given in terms of a quotient of two wronskians of order N depending on 2 N real parameters. When one of these parameters goes to 0, we succeed to get for each positive integer N , rational solutions as a quotient of polynomials in x and t depending on 2 N real parameters. We construct explicit expressions of these rational solutions for orders N = 1 until N = 6 .
Antennal sensilla ofNeomysis integer (leach)
1978
The most frequent type of the hair sensilla on the antennae ofNeomysis integer is investigated by electron microscopic methods. The cellular properties of the sensilla are compared with those of other arthropods in order to detect possible homologies.
Effect of rootstock on trunk growth and foliar mineral content in cv. Bianca pistachio (Pistacia vera L.) trees
1998
Trunk cross-sectional area (TCSA) and mineral content were recorded for 4 years in the major Sicilian pistachio cultivar, Bianca, budded in 1991 onto eight in v/fro-propagated clonal rootstocks (Pistacia atlantica and P. integerrima) and one seedling rootstock (P. terebinthus). The trees were grown using standard cultural practices for Sicilian dry-land farming in a fine sandy soil, located inland in Sicily (20 km SW of Palermo, 350 m a.s.l.). From nine trees per rootstock, samples of 10 leaflets from the mid-section of current year shoots were taken yearly in August and analyzed for the main plant mineral elements (N, P, K, Ca, Mg, Fe, Mn, Zn, Cu and B). The TCSA was measured at the end of…
Flexibility Services in a Mediterranean Small Island to Minimize Costs and Emissions Related to Electricity Production from Fossil Fuels
2020
In last years, the energy efficiency in non-interconnected islands became an important topic, since the electricity production is often based on diesel generators, thus contributing to the global warming. Italian government recently emitted two decrees to promote the introduction of renewable energy technologies in 21 non-interconnected islands, both for electrical and thermal uses. In this paper, the economic and environmental feasibility of the introduction of renewable energies in the island of Pantelleria was assessed adopting an optimization approach. Furthermore, the flexibility provided from the local desalination plant and the domestic water heaters was evaluated. The final demands …