Authors:N. Abrosimov, E. Makai, A. Mednykh, Yu. Nikonorov, and G. Rote
We prove the theorem mentioned in the title for ℝn where n ≧ 3. The case of the simplex was known previously. Also the case n = 2 was settled, but there the infimum was some well-defined function of the side lengths. We also consider the cases of spherical and hyperbolic n-spaces. There we give some necessary conditions for the existence of a convex polytope with given facet areas and some partial results about sufficient conditions for the existence of (convex) tetrahedra.
On étudie la positivité complète du noyau de convolution multiplicatif T associé au produit de deux variables aléatoires indépendantes B(a, b) et Γ(c). Ce noyau T est complétement positif d’ordre infini si b ∈ ℕ* ou si d = a + b − c ∈ ℕ. Dans les autres cas la régularité du signe de T a toujours un ordre fini, qui est ici calculé. Plus précisément, pour tout n ≧ 1 on montre que T est complètement positif d’ordre n + 1 si et seulement si (d, b) est situé au dessus d’un certain escalier
We analyse the oscillation and non-oscillation of second-order half-linear differential equations with periodic and asymptotically almost periodic coefficients, where the equations have the so-called Riemann-Weber form. For these equations, we find an explicit oscillation constant. Corollaries and examples are mentioned as well.
of double sequences whose Cesàro transforms are bounded, convergent in the Pringsheim’s sense, null in the Pringsheim’s sense, both convergent in the Pringsheim’s sense and bounded, regularly convergent and absolutely q-summable, respectively, and also examine some properties of those sequence spaces. Furthermore, we show that these sequence spaces are Banach spaces. We determine the alpha-dual of the space
In this paper we study left amenability of Lau algebras by introducing left approximate diagonal and virtual diagonal for Lau algebras. Some results related to Hahn-Banach theorem property on foundation topological semigroups are obtained. We introduce the left contractibility of Lau algebras. Some examples for clarifying that left contractibility of Lau algebras is stronger than left amenability of them are given.
The problem when a paratopolgical group (or semitopological group) is a topological group is interesting and important. In this paper, we continue to study this problem. It mainly shows that: (1) Let G be a paratopological group and put τ = ωHs(G); then G is a topological group if G is a Pτ-space; (2) every co-locally countably compact paratopological group G with ωHs(G) ≦ ω is a topological group; (3) every co-locally compact paratopological group is a topological group; (4) each 2-pseudocompact paratopological group G with ωHs(G) ≦ ω is a topological group. These results improve some results in [11, 13].
Let (R, m) be a Noetherian local ring and M a finitely generated R-module. In this paper, we study some invariants of the idealization R ⋉ M of R and M such as the polynomial type introduced by Cuong  and the polynomial type of fractions introduced by Cuong-Minh . As consequences, we characterize the Cohen-Macaulay, generalized Cohen-Macaulay, pseudo Cohen-Macaulay and pseudo generalized Cohen-Macaulay properties of the idealization R ⋉ M.
In this note the proof of a slight generalization of the Maximal Ergodic Inequality is a bit simplified and it is shown that from this generalized inequality Birkhoff’s Pointwise Ergodic Theorem follows almost immediately.
This paper is devoted to studying a q-analogue of Sturm-Liouville operators. We formulate a dissipative q-difference operator in a Hilbert space. We construct a self adjoint dilation of such operators. We also construct a functional model of the maximal dissipative operator which is based on the method of Pavlov and define its characteristic function. Finally, we prove theorems on the completeness of the system of eigenvalues and eigenvectors of the maximal dissipative q-Sturm-Liouville difference operator.