Results 21 to 30 of about 46,964 (266)
Characterizations of semiperfect and perfect rings [PDF]
, 1996 We characterize semiperfect modules, semiperfect rings, and perfect rings using locally projective covers and generalized locally projective covers, where locally projective modules were introduced by Zimmermann-Huisgen and generalized locally projective
Xue, Weimin
core +2 more sources
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
doaj +1 more source
ORBIFOLD GROUPS, QUASI-PROJECTIVITY AND COVERS [PDF]
Journal of Singularities, 2012 20 ...
Bartolo, Enrique Artal +2 more
openaire +2 more sources
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
doaj +1 more source
Numerical calculation of three-point branched covers of the projective line [PDF]
, 2013 We exhibit a numerical method to compute three-point branched covers of the complex projective line. We develop algorithms for working explicitly with Fuchsian triangle groups and their finite index subgroups, and we use these algorithms to compute power
Klug, Michael +3 more
core +2 more sources
Quasi-projective covers of right $S$-acts [PDF]
Categories and General Algebraic Structures with Applications, 2014 In this paper $S$ is a monoid with a left zero and $A_S$ (or $A$) is a unitary right $S$-act. It is shown that a monoid $S$ is right perfect (semiperfect) if and only if every (finitely generated) strongly flat right $S$-act is quasi-projective.
Mohammad Roueentan, Majid Ershad
doaj
The Cohen-Macaulay representation type of arithmetically Cohen-Macaulay varieties [PDF]
, 2017 We show that all reduced closed subschemes of projective space that have a Cohen-Macaulay graded coordinate ring are of wild Cohen-Macaulay type, except for a few cases which we completely classify.Comment: Completely new version.
Faenzi, Daniele, Pons-Llopis, Joan
core +4 more sources
Semi-perfect and F-semi-perfect modules
International Journal of Mathematics and Mathematical Sciences, 1985 A module is semi-perfect iff every factor module has a projective cover. A module M=A+B (for submodules A and B) is amply supplemented iff there exists a submodule A′ (called a supplement of A) of B such M=A+A′ and A′ is minimal with this property.
David J. Fieldhouse
doaj +1 more source
DYNAMICS OF ILLUMINANCE INCIDENT ON THE LANW SURFACE IN THE SHADE OF VARIOUS WOODY SPECIES
Юг России: экология, развитие, 2019 Aim. This paper is aimed at studying the relative light conditions (RLC) for lawns in the crown shade of light‐requiring and shade‐tolerant trees from the landscaping sites of Stavropol.Methods.
L. A. Grechushkina‐Sukhorukova
doaj +1 more source
Cyclically presented modules, projective covers and factorizations
, 2013 We investigate projective covers of cyclically presented modules, characterizing the rings over which every cyclically presented module has a projective cover as the rings $R$ that are Von Neumann regular modulo their Jacobson radical $J(R)$ and in which
Facchini, Alberto +2 more
core +1 more source