Commutative Objects, Central Morphisms and Subtractors in Subtractive Categories

Partial Morphisms in Categories of Effective Objects

Gorenstein projective objects in Abelian categories

Let $mathcal {A}$ be an abelian category with enough projective objects and $mathcal {X}$ be a full subcategory of $mathcal {A}$. We define Gorenstein projective objects with respect to $mathcal {X}$ and $mathcal{Y}_{mathcal{X}}$, respectively, where $mathcal{Y}_{mathcal{X}}$=${ Yin Ch(mathcal {A})| Y$ is acyclic and $Z_{n}Yinmathcal{X}}$. We point out that under certain hypotheses, these two G...

Commutative ring objects in pro-categories and generalized Moore spectra

We develop a rigidity criterion to show that in simplicial model categories with a compatible symmetric monoidal structure, operad structures can be automatically lifted along certain maps. This is applied to obtain an unpublished result of M. J. Hopkins that certain towers of generalized Moore spectra, closely related to the K(n)-local sphere, are E∞-algebras in the category of pro-spectra. In...

kurdish diaspora in central asia and caoucasus

در طول دو قرن گذشته و ظهور روسیه بعنوان قدرتی بزرگ در عرصه جهانی و شروع رقابت با سایر قدرت های بین المللی و منطقهای خصوصا با ایران و عثمانی این ئکشور تلاش کرده است تاد از جمعیت کردها در این کشورها در راستای منافع خود بهره برداری کند در قرون 18 و 19 بارها بخشی از کردها برعلیه امپراطوری عثمانی توسط این کشور مورد استفاده قرار گرفت خصوصا در جنگ های سال 1790تا 1798. این ججنگ ها م.جب شد که بخشی از کر...

Dense Morphisms in Commutative Banach Algebras

Using a new notion of stability we compute exactly the stable rank of the polydisc algebra, extend Oka's extension theorem to «-tuples of functions without common zeros and give an estimation for a question raised by Swan concerning the stable rank of a dense subalgebra of a given Banach algebra. 0. Introduction. The stable rank of a ring A [2] is an algebraic invariant of A which turns out to ...