Let $R$ be a unitary ring with an endomorphism $σ$ and $F∪{0}$ be the free monoid generated by $U={u_1,…,u_t}$ with $0$ added, and $M$ be a factor of $F$ setting certain monomial in $U$ to $0$, enough so that, for some natural number $n$, $M^n=0$. In this paper, we give a sufficient condition for a ring $R$ such that the skew monoid ring $R*M$ is quasi-Armendariz (By Hirano a ring $R$ is called...

We study families of Galois covers curves positive genus. It is known that under a numerical condition these yield Shimura subvarieties generically contained in the Jacobian locus. prove there are only 6 satisfying this condition, all them genus 2,3 or 4. also show admit two fibrations totally geodesic subvarieties, generalizing result Grushevsky and M\oller. Countably many fibres Shimura. Thus...

‎let $g_{i} $ be a subgroup of $ s_{m_{i}}‎ ,‎ 1 leq i leq k$‎. ‎suppose $chi_{i}$ is an irreducible complex character of $g_{i}$‎. ‎we consider $ g_{1}times cdots times g_{k} $ as subgroup of $ s_{m} $‎, ‎where $ m=m_{1}+cdots‎ +‎m_{k} $‎. ‎in this paper‎, ‎we give a formula for the dimension of $h_{d}(g_{1}times cdots times g_{k}‎, ‎chi_{1}timescdots times chi_{k})$ and investigate the existe...

in this work, by employing the krasnosel'skii fixed point theorem, we study the existence of positive solutions of a three-point boundary value problem for the following fourth-order differential equation begin{eqnarray*} left { begin{array}{ll} u^{(4)}(t) -f(t,u(t),u^{prime prime }(t))=0 hspace{1cm} 0 leq t leq 1, & u(0) = u(1)=0, hspace{1cm} alpha u^{prime prime }(0) - beta u^{prime prime...

Let $P_n(y_1,\ldots,y_n):= \prod_{1\leq i<j\leq n}\left( 1 -\frac{y_i}{y_j}\right) $ and $P_n:= \sup_{(y_1,\ldots,y_n)}P_n(y_1,\ldots,y_n) where the supremum is taken over $n$-ples $(y_1,\ldots,y_n)$ of real numbers satisfying $0 <|y_1| < |y_2|< \cdots |y_n|$. We prove that $P_n \leq 2^{\lfloor n/2\rfloor}$ for every $n$, i.e., we extend to all $n$ bound Pohst proved $n\leq 11$. As a consequenc...

SUMMARY This document describes the basis of the computer model currently used by the CAA to generate contour maps of aircraft noise exposure level around airports. Developed from the earlier Noise and Number Index (NNI) model, this now produces contours of Equivalent Sound Level (Leq) in dB(A). The main difference between the procedures used to compute these two noise indices lies in the algor...

J. E. Byers ([email protected]) and C. L. Keogh, Odum School of Ecology, Univ. of Georgia, Athens, GA 30602, USA. – A. J. Malek and L. E. Quevillon, Shoals Marine Laboratory, Univ. of New Hampshire, 24 Colovos Rd., School of Marine Science and Ocean Engineering, Durham, NH 03824, USA. Present address for AJM: Graduate School of Oceanography, Univ. of Rhode Island, Narragansett, RI 02882, USA. Pre...