elm (ulmus glabra hudson) is one of the most valuable species which distribute all over the caspian forests. nowadays, elm is considered an endangered species due to intensive human activities and outbreak of dutch elm disease over the last few decades. to suitable management of elm, there is need to have indices which describe; current structure and its changes across the time. this study besi...

This paper deals with descriptive complexity of picture languages of any dimension by syntactical fragments of existential second-order logic. • We uniformly generalize to any dimension the characterization by Giammarresi et al. [GRST96] of the class of recognizable picture languages in existential monadic second-order logic. • We state several logical characterizations of the class of picture ...

We introduce a new notion of algorithmic stability, which we call training stability. We show that training stability is sufficient for good bounds on generalization error. These bounds hold even when the learner has infinite VC dimension. In the PAC setting, training stability gives necessary and sufficient conditions for exponential convergence, and thus serves as a distribution-dependent ana...

Abstract We show the equivalences of several notions entropy, like a version topological entropy geodesic flow and Minkowski dimension boundary, in metric spaces with convex bicombings satisfying uniform packing condition. Similar estimates will be given case closed subsets boundary Gromov-hyperbolic bicombings.

let r be an associative ring with identity, c(r) be the category of com-plexes of r-modules and flat(c(r)) be the class of all at complexes of r-modules. we show that the at cotorsion theory (flat(c(r)); flat(c(r))−)have enough injectives in c(r). as an application, we prove that for each atcomplex f and each complex y of r-modules, exti (f,x)= 0, whenever ris n-perfect and i > n.

In this paper, we discuss the competition of two species for a single essential growth-limiting nutriment with viral infection that affects only first species. Although classical models without suggest competitive exclusion, model exhibits stable coexistence both We reduce fourth-dimension proposed to three-dimension one. Thus, competing is demonstrated using theory uniform persistence applied ...

Abstract We study normal reflection subgroups of complex groups. Our approach leads to a refinement theorem Orlik and Solomon the effect that generating function for fixed-space dimension over group is product linear factors involving generalised exponents. gives uniform proof generalisation recent second author.

Positivity preserving properties have been conjectured for the bilaplace Dirichlet problem in many versions. In this note we show that in any dimension there exist bounded smooth domains Ω such that even the solution of ∆u = 1 in Ω with the homogeneous Dirichlet boundary conditions u = uν = 0 on ∂Ω is sign-changing. In two dimensions this corresponds to the Kirchhoff-Love model of a clamped pla...

Metal oxide surge arresters (ZNO) are used widely in power system to protect equipments from over voltages. Non uniform potential distribution leads to the depressed service life and low safe reliability, so grading ring is applied on HV surge arrester order to uniform the electric field distribution. One of the problems of arresters is leakage current in power frequency that different paramet...

We present a detailed study of spatially propagating waves in a discontinuous Galerkin scheme applied to a system of linear hyperbolic equations. We start with an eigensolution analysis of the semi-discrete system in one space dimension with uniform grids. It is found that, for any given order of the basis functions, there are at most two spatially propagating numerical wave modes for each phys...