Wang, Aifa Shao, Yong
Published in
Open Mathematics

The aim of this paper is to study the lattice of subvarieties of the ai-semiring variety defined by the additional identities xp+1≈xandzxyz≈(zxzyz)pzyxz(zxzyz)p, $$\begin{array}{} \displaystyle x^{p+1}\approx x\,\,\mbox{and}\,\,zxyz\approx(zxzyz)^{p}zyxz(zxzyz)^{p}, \end{array} $$ where p is a prime. It is shown that this lattice is a distributive ...

Cui, Lu-Bin Li, Ming-Hui
Published in
Open Mathematics

The limit point 𝓧 of an approximating rank-R sequence of a tensor Ƶ can be obtained by fitting a decomposition (S, T, U) ⋅ 𝓖 to Ƶ. The decomposition of the limit point 𝓧 = (S, T, U) ⋅ 𝓖 with 𝓖 = blockdiag(𝓖1, … , 𝓖m) can be seen as a three order generalization of the real Jordan canonical form. The main aim of this paper is to study under what cond...

Long, Yuhua Shi, Haiping Deng, Xiaoqing
Published in
Open Mathematics

In this paper some sufficient conditions are obtained to guarantee the existence of nontrivial 4T + 2 periodic solutions of asymptotically linear delay difference equations. The approach used is based on Morse theory.

Mojdeh, Doost Ali Musawi, S.R. Nazari, E.
Published in
Open Mathematics

A subset D of vertices of a graph G is a dominating set if for each u ∈ V(G) ∖ D, u is adjacent to some vertex v ∈ D. The domination number, γ(G) of G, is the minimum cardinality of a dominating set of G. For an even integer n ≥ 2 and 1 ≤ Δ ≤ ⌊log2 n⌋, a Knödel graph WΔ, n is a Δ-regular bipartite graph of even order n, with vertices (i, j), for i ...

Jia, Xiaoyao Ding, Xiaoquan Gao, Juanjuan
Published in
Open Mathematics

In this paper we investigate the stochastic retarded reaction-diffusion equations with multiplicative white noise on unbounded domain ℝn (n ≥ 2). We first transform the retarded reaction-diffusion equations into the deterministic reaction-diffusion equations with random parameter by Ornstein-Uhlenbeck process. Next, we show the original equations g...

Guo, Junying Guo, Xiaojiang
Published in
Open Mathematics

Strict RA semigroups are common generalizations of ample semigroups and inverse semigroups. The aim of this paper is to study algebras of strict RA semigroups. It is proved that any algebra of strict RA semigroups with finite idempotents has a generalized matrix representation whose degree is equal to the number of non-zero regular 𝓓-classes. In pa...

Kasim, Ehmet Gupur, Geni
Published in
Open Mathematics

In this paper, we study the asymptotic property of underlying operator corresponding to the M/G/1 queueing model with single working vacation, where both service times in a regular busy period and in a working vacation period are function. We obtain that all points on the imaginary axis except zero belong to the resolvent set of the operator and ze...

Tang, Chao-Hong Li, Hong-Xu
Published in
Open Mathematics

In this paper, we introduce the concept of Sp-pseudo almost periodicity on time scales and present some basic properties of it, including the translation invariance, uniqueness of decomposition, completeness and composition theorem. Moreover, we prove the seemingly simple but nontrivial result that pseudo almost periodicity implies Stepanov-like ps...

Osipov, Alexander V.
Published in
Open Mathematics

In paper we prove that: a space of Borel functions B(X) on a set of reals X, with pointwise topology, to be countably selective sequentially separable if and only if X has the property S1(BΓ, BΓ); there exists a consistent example of sequentially separable selectively separable space which is not selective sequentially separable. This is an answer ...

Castro, Ildefonso Castro-Infantes, Ildefonso Castro-Infantes, Jesús
Published in
Open Mathematics

This article is motivated by a problem posed by David A. Singer in 1999 and by the classical Euler elastic curves. We study spacelike and timelike curves in the Lorentz-Minkowski plane 𝕃2 whose curvature is expressed in terms of the Lorentzian pseudodistance to fixed geodesics. In this way, we get a complete description of all the elastic curves in...