A digraph H is immersed in a digraph G if the vertices of H are mapped to (distinct) vertices of G, and the edges of H are mapped to directed paths joining the corresponding pairs of vertices of G, in such a way that the paths are pairwise edge-disjoint. For graphs the same relation (using paths instead of directed paths) is a well-quasi-order; that is, in every infinite set of graphs some one ...

We show that there exists a homeomorphism from the hyperspace of the Hubert cube Q onto the countable product of Hubert cubes such that the > A:-dimensional sets are mapped onto B x Q x Q x • , where B is the pseudoboundary of Q. In particular, the infinitedimensional compacta are mapped onto B , which is homeomorphic to the countably infinite product of lj. In addition, we prove for k G { 1 , ...

In 2013, Tommi Lehtinen and Alexander Okhotin proved that if X is a code, then it has infinite deciphering delay if and only if there exist + ∈ A z y x , , with * , , , X zy yz xy x ∈ and * , X z y ∉ . In this paper, we give a sufficient and necessary condition for codes with infinite deciphering delay. Then, we construct two kinds of three-element codes with infinite deciphering delay.

In order to study the spectral decomposition (a,f(a» of Procaccia of the limit set L(G) of a finitely generated Fuchsian group G of rigid movements in the hyperbolic half plane IH, it is necessary to calculate the a of each element of L(G). Each such element is an allowed infinite word, each letter a generator of G. In this paper we calculate first the 0' of the periodic infinite words, and use...

An ideal conductor electrode in contact with a semi-infinite two-dimensional twocomponent plasma in an external potential is considered. The model is mapped onto an integrable sine-Gordon theory with Dirichlet boundary conditions. The information gained from the mapping provides an explicit form of the surface tension in the plasma-stability regime.

We consider an unusual singular position=dependent-mass particle in an infinite potential well. The corresponding Hamiltonian is mapped through a point-canonical-transformation and an explicit correspondence between the target Hamiltonian and a Pöschl-Teller type reference Hamiltonian is obtained. New ordering ambiguity parametric setting are suggested. PACS codes: 03.65.Ge, 03.65.Ca

In several problems of interest in computational modeling there is a media that is either infinite or semi-infinite. Some examples include: modeling the ocean when doing ship analysis, modeling the soil underneath a footing, and modeling the air around an airplane. However, every finite element model must be terminated at some finite boundary. Unfortunately, for problems involving wave propagat...

We show that in the setting of fair-coin measure on the power set of the natural numbers, each sufficiently random set has an infinite subset that computes no random set. That is, there is an almost sure event A such that if X ∈ A then X has an infinite subset Y such that no element of A is Turing computable from Y .