scholarly journals The Yoneda Algebra of a 𝒦2Algebra Need not be Another 𝒦2Algebra

2009 ◽  
Vol 38 (1) ◽  
pp. 46-48 ◽  
Author(s):  
Thomas Cassidy ◽  
Christopher Phan ◽  
Brad Shelton
Keyword(s):  
Yoneda Algebra

scholarly journals THE HOMOGENISED ENVELOPING ALGEBRA OF THE LIE ALGEBRA sℓ(2,ℂ)

2014 ◽  
Vol 56 (3) ◽  
pp. 551-568 ◽  
Author(s):  
ROBERTO MARTINEZ-VILLA
Keyword(s):  
Lie Algebra ◽  
Projective Dimension ◽  
Global Dimension ◽  
Verma Modules ◽  
Regular Component ◽  
Koszul Duality ◽  
Koszul Algebra ◽  
Yoneda Algebra ◽  
Enveloping Algebra ◽  
Wild Algebra

AbstractIn this paper, we study the homogenised algebra B of the enveloping algebra U of the Lie algebra sℓ(2,ℂ). We look first to connections between the category of graded left B-modules and the category of U-modules, then we prove B is Koszul and Artin–Schelter regular of global dimension four, hence its Yoneda algebra B! is self-injective of radical five zeros, and the structure of B! is given. We describe next the category of homogenised Verma modules, which correspond to the lifting to B of the usual Verma modules over U, and prove that such modules are Koszul of projective dimension two. It was proved in Martínez-Villa and Zacharia (Approximations with modules having linear resolutions, J. Algebra266(2) (2003), 671–697)] that all graded stable components of a self-injective Koszul algebra are of type ZA∞. Here, we characterise the graded B!-modules corresponding to the Koszul duality to homogenised Verma modules, and prove that these are located at the mouth of a regular component. In this way we obtain a family of components over a wild algebra indexed by ℂ.

scholarly journals Conditions for the Yoneda algebra of a local ring to be generated in low degrees

2017 ◽  
Vol 221 (2) ◽  
pp. 304-315 ◽  
Author(s):  
Justin Hoffmeier ◽  
Liana M. Şega
Keyword(s):  
Local Ring ◽  
Yoneda Algebra ◽  
Low Degrees

MODULES WITH PURE RESOLUTIONS OVER KOSZUL ALGEBRAS

2014 ◽  
Vol 13 (05) ◽  
pp. 1350159 ◽  
Author(s):  
JIAFENG LÜ
Keyword(s):  
Jacobson Radical ◽  
Koszul Algebras ◽  
Finitely Generated ◽  
Koszul Algebra ◽  
Yoneda Algebra

Let A be a Koszul algebra and M a finitely generated graded A-module. Suppose that M is generated in degree 0 and has a pure resolution. We prove that, if rℰ(M) ≠ 0 then M is Koszul; and if in addition M is not projective, then the converse is true as well, where r denotes the graded Jacobson radical of the Yoneda algebra [Formula: see text] of A, and [Formula: see text] denotes the Ext module of M.

scholarly journals Koszulity and Point Modules of Finitely Semi-Graded Rings and Algebras

Symmetry ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 881 ◽  
Author(s):  
Oswaldo Lezama ◽  
Jaime Gomez
Keyword(s):  
Mirror Symmetry ◽  
Hilbert Series ◽  
Poincaré Series ◽  
Graded Rings ◽  
Yoneda Algebra ◽  
Graded Algebras ◽  
Poincare Series ◽  
Rings And Algebras ◽  
Lattice Of Ideals ◽  
Point Modules

In this paper, we investigate the Koszul behavior of finitely semi-graded algebras by the distributivity of some associated lattice of ideals. The Hilbert series, the Poincaré series, and the Yoneda algebra are defined for this class of algebras. Moreover, the point modules and the point functor are introduced for finitely semi-graded rings. Finitely semi-graded algebras and rings include many important examples of non- N -graded algebras coming from mathematical physics that play a very important role in mirror symmetry problems, and for these concrete examples, the Koszulity will be established, as well as the explicit computation of its Hilbert and Poincaré series.

scholarly journals The Yoneda Algebra of a Graded Ore Extension

2012 ◽  
Vol 40 (3) ◽  
pp. 834-844 ◽  
Author(s):  
Christopher Phan
Keyword(s):  
Ore Extension ◽  
Yoneda Algebra

Modules with pure resolutions over Koszul algebras revisited

2015 ◽  
Vol 15 (02) ◽  
pp. 1650035 ◽  
Author(s):  
Thomas Cassidy
Keyword(s):  
Jacobson Radical ◽  
Koszul Algebras ◽  
Finitely Generated ◽  
Koszul Algebra ◽  
Yoneda Algebra ◽  
Koszul Module

I construct a Koszul algebra A and a finitely generated graded A-module M that together form a counterexample to a recently published claim. M is generated in degree 0 and has a pure resolution, and the graded Jacobson radical of the Yoneda algebra of A does not annihilate the Ext module of M, but nonetheless M is not a Koszul module.

On the Yoneda Ext-Algebras of Semiperfect Algebras

2008 ◽  
Vol 15 (02) ◽  
pp. 207-222 ◽  
Author(s):  
Jiwei He ◽  
Yu Ye
Keyword(s):  
Jacobson Radical ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
Yoneda Algebra ◽  
Ideal Formula ◽  
Morita Equivalent ◽  
Morita Invariant ◽  
The Right ◽  
Necessary And Sufficient

It is proved that the Yoneda Ext-algebras of Morita equivalent semiperfect algebras are graded equivalent. The Yoneda Ext-algebras of noetherian semiperfect algebras are studied in detail. Let A be a noetherian semiperfect algebra with Jacobson radical J. We construct a right ideal [Formula: see text] of the Yoneda algebra [Formula: see text], which plays an important role in the discussion of the structure of E(A). An extra grading is introduced to [Formula: see text], by which we give a description of the right ideal of E(A) generated by [Formula: see text], and we give a necessary and sufficient condition for a notherian semiperfect algebra to be higher quasi-Koszul. Finally, it is shown that the quasi-Koszulity of a noetherian semiperfect algebra is a Morita invariant.

scholarly journals HIGHER KOSZUL DUALITY FOR ASSOCIATIVE ALGEBRAS

2013 ◽  
Vol 55 (A) ◽  
pp. 55-74 ◽  
Author(s):  
VLADIMIR DOTSENKO ◽  
BRUNO VALLETTE
Keyword(s):  
Algebraic Structure ◽  
Duality Theory ◽  
Koszul Complex ◽  
General Notion ◽  
Koszul Duality ◽  
Associative Algebras ◽  
Yoneda Algebra ◽  
Dual Algebra ◽  
Key Concepts ◽  
Homogeneous Algebras

AbstractWe present a unifying framework for the key concepts and results of higher Koszul duality theory for N-homogeneous algebras: the Koszul complex, the candidate for the space of syzygies and the higher operations on the Yoneda algebra. We give a universal description of the Koszul dual algebra under a new algebraic structure. For that we introduce a general notion: Gröbner bases for algebras over non-symmetric operads.

scholarly journals Finiteness conditions on the Yoneda algebra of a monomial algebra

2014 ◽  
Vol 218 (1) ◽  
pp. 52-64 ◽  
Author(s):  
Andrew Conner ◽  
Ellen Kirkman ◽  
James Kuzmanovich ◽  
W. Frank Moore
Keyword(s):  
Yoneda Algebra ◽  
Finiteness Conditions ◽  
Monomial Algebra

scholarly journals ON THE EXISTENCE OF A DERIVED EQUIVALENCE BETWEEN A KOSZUL ALGEBRA AND ITS YONEDA ALGEBRA

2014 ◽  
Vol 13 (04) ◽  
pp. 1350136
Author(s):  
R. M. AQUINO ◽  
E. N. MARCOS ◽  
S. TREPODE
Keyword(s):  
Sufficient Conditions ◽  
Derived Categories ◽  
Koszul Algebras ◽  
Derived Equivalence ◽  
Koszul Algebra ◽  
Yoneda Algebra ◽  
Hereditary Algebras ◽  
Yoneda Algebras ◽  
Necessary And Sufficient ◽  
Simply Connected

In this paper, we study the derived categories of a Koszul algebra and its Yoneda algebra to determine when those categories are triangularly equivalent. We prove that the simply connected Koszul algebras are derived equivalent to their Yoneda algebras. We have considered discrete Koszul algebras and we gave necessary and sufficient conditions for those Koszul algebras to be derived equivalent to their Yoneda algebras. We also study the class of Koszul algebras which are derived equivalent to hereditary algebras. For the case where the hereditary algebra is tame, we characterized the derived equivalence between those Koszul algebras and their Yoneda algebras.

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