In this note we observe that, contrary to the usual lore, string orbifolds do not describe strings on quotient spaces, but rather seem to describe strings on objects called quotient stacks, a result that follows from simply unraveling definitions, and is further justified by a number of results. Quotient stacks are very closely related to quotient spaces; for example, when the orbifold group ac...

We study the O(N) symmetric linear sigma model at finite temperature as the low-energy effective models of quantum chromodynamics(QCD) using the CornwallJackiw-Tomboulis(CJT) effective action for composite operators. It has so far been claimed that the Nambu-Goldstone theorem is not satisfied at finite temperature in this framework unless the large N limit in the O(N) symmetry is taken. We show...

there has been considerable number of papers published related to six sigma applications in manufacturing and service organizations. however, very few studies are done on reviewing the literature of six sigma in all the areas including manufacturing, construction, education, financial service, bpos and healthcare etc. considering the contribution of six sigma in recent time, a more comprehensiv...

There has been considerable number of papers published related to Six Sigma applications in manufacturing and service organizations. However, very few studies are done on reviewing the literature of Six Sigma in all the areas including manufacturing, construction, education, financial service, BPOs and healthcare etc. Considering the contribution of Six Sigma in recent time, a more comprehens...

1287 Commentary—Colrain and Baker data showing differences between 15-16 and 17-18 years, with those collected in a similar design but from younger adolescents highlights the fact that later adolescents are still showing dramatic changes in sleep EEG power, reflecting ongoing changes in brain development. Tarokh et al. show smaller changes in the occipital (particularly left occipital) derivati...

We build a systematic calculational method for the covariant expansion of two-point heat kernel $\stackrel{^}{K}(\ensuremath{\tau}|x,{x}^{\ensuremath{'}})$ generic minimal and nonminimal differential operators any order. This is in powers dimensional background field objects---the coefficients operator corresponding spacetime vector bundle curvatures, suitable renormalization effective theory a...

This paper presents a comparative analysis between two current control strategies, constant source power and generalized Fryze current, used in Active Power Filter (APF) applications having three different modulation methods. The Hysteresis Band (HB) and first-order Delta-Sigma Modulation (DSM) as well as the second-order DSM is applied. The power section of the active power filter is viewed as...

let $mathfrak{l}$ be the virasoro-like algebra and $mathfrak{g}$ itsderived algebra, respectively. we investigate the structure of the lie triplederivation algebra of $mathfrak{l}$ and $mathfrak{g}$. we provethat they are both isomorphic to $mathfrak{l}$, which provides twoexamples of invariance under triple derivation.

let  be a banach algebra and  a derivation. in this paper, it is proved, under certain conditions, that , where  is the jacobson radical of . moreover, we prove that if  is unital and  is a continuous derivation, then , where  denotes the set of all primitive ideals such that  is commutative,  denotes the set of all maximal (modular) ideals such that  is commutative, and  is the set of all non-...