Let A be a standard graded Artinian K-algebra, with char K = 0. We prove the following. 1. A has the Weak Lefschetz Property (resp. Strong Lefschetz Property) if and only if Gr(z)(A) has the Weak Lefschetz Property (resp. Strong Lefschetz Property) for some linear form z of A. 2. If A is Gorenstein, then A has the Strong Lefschetz Property if and only if there exists a linear form z of A such t...

The Fudenberg and Maskin (1986) folk theorem for discounted repeated games assumes that the set of feasible payoffs is full dimensional. We obtain the same conclusion using a weaker condition. This condition is that no pair of players has equivalent von Neumann-Morgenstern utilities over outcomes. We term this condition NEU "non-equivalent utilities". The condition is weak, easily interpreted, ...

Abstract Nowadays there is increasing interest in narrowing coronal areas with reduced brightness temperatures (LTR – Low Temperature Regions) associated local open magnetic fields (S-web, “coronal partings”, “dark corridors”) as one of the eventual sources slow solar wind. Ventspils International Radio Astronomy Centre (VIRAC) performs routine spectral polarimetric observations Sun RT-32 radio...

Patterns of plant distribution by palaeoenvironment were examined across the Pennsylvanian-Permian transition in North-Central Texas. Stratigraphically recurrent packages of distinct lithofacies, representing different habitats, contain qualitatively and quantitatively different macrofloras and microfloras. The species pools demonstrate niche conservatism, remaining closely tied to specific hab...

The highly elevated concentrations of the rare earth elements and yttrium (REY), U, Mo, Se, Pb in late Permian coals some coalfields Guangxi Province, South China, have been widely investigated; however, mode occurrence enrichment mechanism these critical are still under debate. This study investigates mineralogical geochemical compositions non-coal rocks from Xian’an Coalfield Province to disc...

recently, choudhury and metiya [fixed points of weak contractions in cone metric spaces, nonlinear analysis 72 (2010) 1589-1593] proved some fixed point theorems for weak contractions in cone metric spaces. weak contractions are generalizations of the banach's contraction mapping, which have been studied by several authors. in this paper, we introduce the notion of $f$-weak contractions and als...

in this note first we define the notions of fuzzy positive implicativehyper bck-ideals of types 1,2,3 and 4. then we prove some theorems whichcharacterize the above notions according to the level subsets. also we obtainthe relationships among these notions, fuzzy (strong, weak, reflexive) hyperbck-ideals and fuzzy positive implicative hyper bck-ideals of types 5,6,7and 8. then, we define the no...

‎in the present paper we investigate the $l_1$-weak ergodicity of‎ ‎nonhomogeneous continuous-time markov processes with general state‎ ‎spaces‎. ‎we provide a necessary and sufficient condition for such‎ ‎processes to satisfy the $l_1$-weak ergodicity‎. ‎moreover‎, ‎we apply‎ ‎the obtained results to establish $l_1$-weak ergodicity of quadratic‎ ‎stochastic processes‎.