In this paper, we determine some sufficient conditions for an $A\,+\,XB\left[ X \right]$ domain to be an $\text{HFD}$. As a consequencewe give new examples of $\text{HFDs}$ of the type $A\,+\,XB\left[ X \right]$.

We shall provide a characterization of all isoparametric hypersurfaces ${M}'s$ in a real space form $\tilde{M}\left( c \right)$ by observing the extrinsic shape of geodesics of $M$ in the ambient manifold $\tilde{M}\left( c \right)$.

Using spaces introduced by Anick, we construct a decomposition into indecomposable factors of the double loop spaces of odd primary Moore spaces when the powers of the primes are greater than the first power. If $n$ is greater than 1, this implies that the odd primary part of all the homotopy groups of the $2n\,+\,1$ dimensional sphere lifts to a mod ${{p}^{r}}$ Moore space.

Many classes of singularly perturbed reaction-diffusion equations possess localized solutions where the gradient of the solution is large only in the vicinity of certain points or interfaces in the domain. The problems of this type that are considered are an interface propagation model from materials science and an activator-inhibitor model of morphogenesis. These two models are formulated as nonlocal partial differential equations. Results concerning the existence of equilibria, their stability, and the dynamical behavior of localized structures in the interior and on the boundary of the domain are surveyed for these two models. By examining the spectrum associated with the linearization of these problems around certain canonical solutions, it is shown that the nonlocal term can lead to the existence of an exponentially small principal eigenvalue for the linearized problem. This eigenvalue is then responsible for an exponentially slow, or metastable, motion of the localized structure.

We extend Maxwell’s representation of harmonic polynomials to $h$-harmonics associated to a reflection invariant weight function ${{h}_{k}}$. Let ${{\mathcal{D}}_{i}},\,1\,\le \,i\,\le \,d$, be Dunkl’s operators associated with a reflection group. For any homogeneous polynomial $P$ of degree $n$,we prove the polynomial ${{\left| x \right|}^{2\gamma +d-2+2n}}P\left( \mathcal{D} \right)\left\{ 1/{{\left| x \right|}^{2\gamma +d-2}} \right\}$ is a $h$-harmonic polynomial of degree $n$, where $\gamma \,=\,\sum \,ki$ and $\mathcal{D}\,=\,\left( {{\mathcal{D}}_{1}},\ldots ,{{\mathcal{D}}_{d}} \right)$. The construction yields a basis for $h$-harmonics. We also discuss self-adjoint operators acting on the space of $h$-harmonics.

We extend the recent results of R. Latała and O. Guédon about equivalence of ${{L}_{q}}$ -norms of logconcave random variables (Kahane-Khinchin’s inequality) to the quasi-convex case. We construct examples of quasi-convex bodies ${{K}_{n\,}}\subset {{\mathbb{R}}^{n}}$ which demonstrate that this equivalence fails for uniformly distributed vector on ${{K}_{n}}$ (recall that the uniformly distributed vector on a convex body is logconcave). Our examples also show the lack of the exponential decay of the “tail” volume (for convex bodies such decay was proved by M. Gromov and V. Milman).

We prove that ${{\left\{ \left( {{n}^{p}}-n \right)/P \right\}}_{p}}\in {{\Pi }_{p}}{{\text{F}}_{p}}$, with $p$ ranging over all primes, is independent of 1 over the integers, assuming a conjecture in elementary number theory generalizing the infinitude of Mersenne primes. This answers a question of Buium. We also prove a generalization.

An explicit classification is given of blocks of cyclic defect of cyclotomic Schur algebras and of cyclotomic Hecke algebras, over discrete valuation rings.

For an integer $n$, let $d\left( n \right)$ denote the ordinary divisor function. This paper studies the asymptotic behavior of the sum

$$S\left( x \right)\,:=\sum\limits_{m\le x,n\le x}{d\left( {{m}^{2}}+{{n}^{2}} \right)}$$

It is proved in the paper that, as $x\,\to \,\infty $,

$$S(x):={{A}_{1}}{{x}^{2}}\log x+{{A}_{2}}{{x}^{2}}+{{O}_{\in }}({{x}^{\frac{3}{2}+\in }}),$$

where ${{A}_{1}}$ and ${{A}_{2}}$ are certain constants and $\in $ is any fixed positive real number.

The result corrects a false formula given in a paper of Gafurov concerning the same problem, and improves the error $O({{x}^{\frac{5}{3}}}\,{{(\log \,x)}^{9}})$ claimed by Gafurov.

In this note we give a proof of Lomonosov’s extension of Burnside’s theoremto infinite dimensional Banach spaces.

It is shown that given a local $L$-function defined by Langlands-Shahidi method, there exists a highly ramified character of the group which when is twisted with the original representation leads to a trivial $L$-function.

Let $G$ be a hermitian quaternionic group. We determine complementary series for representations of $G$ induced from super-cuspidal representations of a Levi factor of the Siegel maximal parabolic subgroup of $G$.

A counterexample is given to a conjecture of Ikeda by finding a class of Gorenstein rings of embedding dimension 3 with larger Dilworth number than Sperner number. The Dilworth number of $A\left[ {Z}/{pZ}\;\,\oplus \,{Z}/{pZ}\; \right]$ is computed when $A$ is an unramified principal Artin local ring.

We observe that any set of uniqueness for the Dirichlet space $\mathcal{D}$ is a set of uniqueness for the class $S$ of normalized univalent holomorphic functions.

The Four Color Theorem says that the faces (or vertices) of a plane graph may be colored with four colors. Vizing’s Theorem says that the edges of a graph with maximum degree $\Delta$ may be colored with $\Delta \,+\,1$ colors. In 1972, Kronk and Mitchem conjectured that the vertices, edges, and faces of a plane graph may be simultaneously colored with $\Delta \,+\,4$ colors. In this article, we give a simple proof that the conjecture is true if $\Delta \,\ge \,6$.

An infinite family of perfect, non-extremal Riemann surfaces is constructed, the first examples of this type of surfaces. The examples are based on normal subgroups of the modular group $\text{PSL}\left( 2,\,\mathbb{Z} \right)$ of level 6. They provide non-Euclidean analogues to the existence of perfect, non-extremal positive definite quadratic forms. The analogy uses the function syst which associates to every Riemann surface $M$ the length of a systole, which is a shortest closed geodesic of $M$.

Soient $A$ un anneau noethérien, $B$ un anneau régulier essentiellement de type fini sur $A$. Si la cohomologie d’André-Quillen ${{H}^{q}}\left( A,\,B,\,B \right)\,=\,0$ pour tout $q\,\ge \,2$ alors $A$ est un anneau régulier.