This paper is a continuation of my previous paper in Mathematica Bohemica and solves the same problem but by means of another method. It deals with almost periodic solutions of a certain type of almost periodic systems of differential equations.

Some known results on claw-free (K 1;3-free) graphs are generalized to the larger class of almost claw-free graphs which were introduced by Ryjj a cek. In particular, we show that a 2-connected almost claw-free graph is 1-tough, and that a 2-connected almost claw-free graph on n vertices is hamiltonian if 1 3 (n ? 2), thereby (partly) generalizing results of Matthews and Sumner. Finally, we use...

Let G = (V, E) be a connected graph. The distance between two vertices x and y in G, denoted by dG(x, y), is the length of a shortest path between x and y. A graph G is called almost distance-hereditary, if each connected induced subgraph H of G has the property that dH (u, v) ≤ dG(u, v)+ 1 for every pair of vertices u and v in H . We will confirm that every 2-connected, claw-free and almost di...

Given a positive integer n we find a graph G = (V,E) on |V | = n vertices with a minimum number of edges such that for any pair of non adjacent vertices x, y the graph G − x − y contains a (almost) perfect matching M . Intuitively the non edge xy and M form a (almost) perfect matching of G. Similarly we determine a graph G = (V,E) with a minimum number of edges such that for any matching M̄ of t...

let x=(xi, • • ■ , xn) and /=(fi, • • • ,/„), and suppose that / is of class C1. A set, 12, of points x will be called unrestricted if, whenever a point x0 is in 12, the solution path x = x(t), where x0 = x(0), exists for — co </< oo and lies in 12. Two types of stability distinguished simply by "A" and "B" will be considered: (A) Let the value to be arbitrary but fixed. A solution x — x(t) of ...

In this paper, by applying Mawhin’s continuation theorem of coincidence degree theory, we study the existence of almost periodic solutions for neural multi-delay logarithmic population model and obtain one sufficient condition for the existence of positive almost periodic solution for the above equation. An example is employed to illustrate our result. Keywords—Almost periodic solution; Multi-d...

The paper examines the existence of pseudo almost periodic solutions to some classes of partial hyperbolic evolution equations. Namely, sufficient conditions for the existence and uniqueness of pseudo almost periodic solutions to those classes of hyperbolic evolution equations are given. Applications include the existence of pseudo almost periodic solutions to the transport and heat equations w...

We prove that one-dimensional Schrödinger operators with even almost periodic potential have no point spectrum for a dense Gδ in the hull. This implies purely singular continuous spectrum for the almost Mathieu equation for coupling larger than 2 and a dense Gδ in θ even if the frequency is an irrational with good Diophantine properties. §

This article consists in two independent parts. In the first one, we investigate the geometric properties of almost periodicity of model sets (or cut-and-project sets, defined under the weakest hypotheses); in particular we show that they are almost periodic patterns and thus possess a uniform density. In the second part, we prove that the class of model sets and almost periodic patterns are st...

In this paper, we study the existence of almost periodic solutions of neutral differential difference equations with piecewise constant arguments via difference equation methods.