In this paper, some existence and multiplicity results involving eigenvalues are established for a class of degenerate quasilinear elliptic system by using Ekeland's variational principle, the mountain pass theorem and the critical point theory.

In this paper we prove an existence result for some class of variational boundary value problems for quasilinear elliptic equations in the Musielak-Orlicz spaces. Some results concerning the Trace mapping have also been provided, as well as existence results for some strongly nonlinear elliptic equations in Musielak-Orlicz spaces.

The classical Korovkin approximation theory deals with the convergence of a sequence of positive linear operators. When the sequence of positive linear operators does not converge it will be useful to use some summability methods. In this paper we use the Abel method, a sequence-to-function transformation, to study a Korovkin type approximation theorem for positive linear operators acting from a weighted space $C_{\rho_{1}}$ into a weighted space $B_{\rho_{2}}.$ Moreover using the modulus of continuity we also give rate of Abel convergence.

The goal of this paper is to develop some applications of the Lefschetz fixed point theorem to digital images. We also deal with relative and reduced Lefschetz fixed point theorem for digital complexes. We give some examples related to the topic. We calculate the degree of the antipodal map for sphere-like digital images using fixed point properties.

We analyze the dynamics of a class of $\mathbb{Z}_6$-equivariant systems of the form $\dot{z}=pz^2\bar{z}+sz^3\bar{z}^2-\bar{z}^{5},$ where $z$ is complex, the time $t$ is real, while $p$ and $s$ are complex parameters. This study is the natural continuation of a previous work (M.J. Àlvarez, A. Gasull, R. Prohens, Proc. Am. Math. Soc. \textbf{136}, (2008), 1035--1043) on the normal form of $\mathbb{Z}_4$-equivariant systems. Our study uses the reduction of the equation to an Abel one, and provide criteria for proving in some cases uniqueness and hyperbolicity of the limit cycle surrounding either 1, 7 or 13 critical points, the origin being always one of these points.

We study division algebras in an arbitrary linear Gr-category, i.e., a category of finite-dimensional vector spaces graded by a group with associativity constraint given by a 3-cocycle. When the 3-cocycle is non-coboundary, this provides some interesting classes of nonassociative division algebras. In particular, when we work on Gr-categories over the field of real numbers, some quasi-associative version of the quaternions and octonions appear.

We give a sufficient condition for the set of nowhere monotone measures to be a residual $G_{\delta}$ set in a subspace of signed Radon measures on a locally compact second-countable Hausdorff space with no isolated points. We prove that the set of nowhere monotone signed Radon measures on a $d$-dimensional real space $\mathbb{R}^{d}$ is lineable. More specifically, we prove that there exists a vector space of dimension $\mathfrak{c}$ (the cardinality of the continuum) of signed Radon measures on $\mathbb{R}^{d}$ every non-zero element of which is a nowhere monotone measure that is almost everywhere differentiable with respect to the $d$-dimensional Lebesgue measure. Using this result we show that the set of these measures is even maximal dense-lineable in the space of bounded signed Radon measures on $\mathbb{R}^{d}$ that are almost everywhere differentiable with respect to the $d$-dimensional Lebesgue measure.

A. Grothendieck proved at the end of his thesis that the space $\mathcal{O}_M$ of slowly increasing functions and the space $\mathcal{O}_{C}'$ of rapidly decreasing distributions are bornological. Grothendieck's proof relies on the isomorphy of these spaces to a sequence space and we present the first proof that does not utilize this fact by using homological methods and, in particular, the derived projective limit functor.

In the four-peg variant of the Towers of Hanoï game, it is well known that $N$ disks can be transferred from a column to another in $2^{\nabla0}+2^{\nabla 1}+\cdots+2^{\nabla(N-1)}$ moves, where $\nabla n$ denotes the largest integer $p$ such that $p(p+1)/2\leqslant n$, and it was conjectured that this number of moves was the minimum possible. We shall see, in this article, that is is indeed the case.

Dans la variante à quatre colonnes des Tours de Hanoï, on sait bien qu'on peut transférer $N$ disques d'une colonne vers une autre en $2^{\nabla 0}+2^{\nabla 1}+\cdots+2^{\nabla(N-1)}$ mouvements, où $\nabla n$ désigne le plus grand entier $p$ tel que $p(p+1)/2\leqslant n$, et on conjecturait que ce nombre de mouvements était le minimum possible. Nous verrons, dans cet article, que c'est effectivement le cas.