Hasil untuk "math.CO"

Akin Scott, Michele Torielli

We introduce the package combinatorics for the software CoCoA. This package provides a data structure and the necessary methods for computing several known enumerative combinatorial invariants.

Helmut Prodinger

A quick way to compute generating functions related to Pell-Padovan tetranacci numbers and classical sequences of recursions of order two is provided. Eight special instances can be computed at once.

George Kontogeorgiou

We produce a new, shorter construction of a minor-universal planar graph.

Meng Liu

Sela Fried

We initiate the study of the coefficients of the distinct monomials in the expansion of the multivariate polynomials $x_1(x_1+x_2)\cdots(x_1+x_2+\cdots+x_n), n\in\N$. In particular we obtain several results regarding their maximal coefficients.

Damir Yeliussizov

We prove an asymptotic saturation-type version of Rota's basis conjecture. It relies on the connection of Tao's slice rank with unstable tensors from geometric invariant theory.

Seungjai Lee

We investigate the roots of Hilbert quasipolynomials arising from certain rational generating functions.

Sergei Kazenas

In this short paper, a formula for the sequence defined by the nonhomogeneous linear difference equation with variable coefficients is presented. A connection with the homogeneous case is shown.

Asghar Bahmani

We give a counterexample to a conjecture of Wang and Hou related with the sum of the $k$ largest Laplacian eigenvalues of signed graphs.

Victor A. Vassiliev

The rational homology group of the order complex of non-even partitions of a finite set is calculated. A twisted version of the Goresky-MacPherson approach to similar homology calculations is proposed.

Edinah K. Gnang, Jeanine S. Gnang

The present note sketches a theory of constructs.

Rúben Nunes, Amílcar Soares, Leonardo Azevedo et al.

Mihai Ciucu

We deduce Narayana's formula for the number of lattice paths that fit in a Young diagram as a direct consequence of the Gessel-Viennot theorem on non-intersecting lattice paths.

Philippe Robutel, Laurent Niederman, Alexandre Pousse

Tobias Meyer, Bernhard Schweizer

AbstractIn this paper, an approach for controlling the macro‐step size in connection with co‐simulation methods [1, 2, 4] is suggested. The investigated step‐size controller is tailored for semi‐implicit co‐simulation techniques. Concretely, we consider predictor/corrector co‐simulation approaches [3]. By comparing variables from the predictor and the corrector step, an error estimator for the local error can be constructed. Making use of the estimated local error, a step‐size controller for the macro step‐size can be implemented. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Ange Bigeni

On the set of permutations of a finite set, we construct a bijection which maps the 3-vector of statistics $(maj-exc,des,exc)$ to a 3-vector $(maj\_2,\widetilde{des\_2},inv\_2)$ associated with the $q$-Eulerian polynomials introduced by Shareshian and Wachs in \textit{Chromatic quasisymmetric functions, arXiv:1405.4269(2014).}

Yaroslav Shitov

We construct a nontrivial identity which holds in the semigroup of tropical 3-by-3 matrices.

Alexander Kreinin

We consider combinatorial properties of the Mills' ratio, and explore the interplay between a continued fraction expansion for the Mills' ratio, the Laplace polynomials and a new family of combinatorial identities.

Arthur Hoffmann-Ostenhof

The disproved Nash Williams conjecture states that every 4-regular 4-connected graph has a hamiltonian cycle. We show that a modification of this conjecture is equivalent to the Dominating Cycle Conjecture.

R. Nandakumar

We introduce the problem of partitioning 2D regions (usually convex regions) into mutually congruent pieces ('tiles').