Results 11 to 20 of about 871 (252)
Projective Covers of Flat Contramodules [PDF]
International Mathematics Research Notices, 2021 Abstract We show that a direct limit of projective contramodules (over a right linear topological ring) is projective if it has a projective cover. A similar result is obtained for $\infty $-strictly flat contramodules of projective dimension not exceeding $1$, using an argument based on the notion of the topological Jacobson radical ...
Bazzoni, S. +2 more
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Projective Covering Designs [PDF]
Bulletin of the London Mathematical Society, 1993 A \((2,k,v)\) covering design is a pair \((X,{\mathcal F})\) such that \(X\) is a \(v\)-element set and \({\mathcal F}\) is a family of \(k\)-element subsets, called blocks, of \(X\) with the property that every pair of distinct elements of \(X\) is contained in at least one block.
Chee, Yeow Meng, Ling, San
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On symplectic coverings of the projective plane [PDF]
Izvestiya: Mathematics, 2005 We prove that a resolution of singularities of any finite covering of the projective plane branched along a Hurwitz curve $\bar H$ and, maybe, along a line "at infinity" can be embedded as a symplectic submanifold into some projective algebraic manifold equipped with an integer Kähler symplectic form (assuming that if $\bar H$ has negative nodes, then ...
Greuel, G. -M., Kulikov, Vik. S.
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On the Projective Cover of an orbit space [PDF]
Journal of the Australian Mathematical Society. Series A. Pure Mathematics and Statistics, 1989 AbstractIn this paper, we obtain the projective cover of the orbit space X/G in terms of the orbit space of the projective space of X, when X is a Tychonoff G-space and G is a finite discrete group. An example shows that finiteness of G is needed.
Azad, K. K., Agrawal, Gunjan
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Projective covers and minimal free resolutions
International Journal of Mathematics and Mathematical Sciences, 1996 Using a generalization of the definition of the projective cover of a module, a special type of surjective free resolution, known as the projective cover of a complex, may be defined.
Mark A. Goddard
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Epimorphisms and maximal covers in categories of compact spaces
Applied General Topology, 2013 The category C is "projective complete"if each object has a projective cover (which is then a maximal cover). This property inherits from C to an epireflective full subcategory R provided the epimorphisms in R are also epi in C. When this condition fails,
B. Banaschewski, A.W. Hager
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Embeddings of covering projections of graphs
Journal of Combinatorial Theory, Series B, 1980 AbstractIt is shown that any given k-fold covering projection of graphs p: G1 → G2 can be embedded in a k-fold covering projection of closed orientable surfaces π: S1 → S2 in the sense that there are embeddings of G1 in S1 and G2 in S2 such that p is the restriction of π.
F. W. Clarke, A. D. Thomas, D. A. Waller
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δss-supplemented modules and rings
Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2020 In this paper, we introduce the concept of δss-supplemented modules and provide the various properties of these modules. In particular, we prove that a ring R is δss-supplemented as a left module if and only if RSoc(RR){R \over {Soc\left( {_RR} \right)}}
Türkmen Burcu Nişancı +1 more
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Flat covers of representations of the quiver A∞
International Journal of Mathematics and Mathematical Sciences, 2003 Rooted quivers are quivers that do not contain A∞≡⋯→•→• as a subquiver. The existence of flat covers and cotorsion envelopes for representations of these quivers have been studied by Enochs et al.
E. Enochs +3 more
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Injective Envelopes and Projective Covers of Quivers [PDF]
The Electronic Journal of Combinatorics, 2012 This paper characterizes the injective and projective objects in the category of directed multigraphs, or quivers. Further, the injective envelope and projective cover of any quiver in this category is constructed.
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