1,720,961 research outputs found
Deformations of algebraic schemes via Reedy–Palamodov cofibrant resolutions
Full text linkLet X be a Noetherian separated and finite dimensional scheme over a field K of characteristic zero. The goal of this paper is to study deformations of X over a differential graded local Artin K-algebra by using local Tate–Quillen resolutions, i.e., the algebraic analogous of the Palamodov's resolvent of a complex space. The above goal is achieved by describing the DG-Lie algebra controlling deformation theory of a diagram of differential graded commutative algebras, indexed by a direct Reedy category
Formal deformation theory in left-proper model categories
Full text linkWe develop the notion of deformation of a morphism in a left-proper model category. As an application we provide a geomet-ric/homotopic description of deformations of commutative (non-positively) graded differential algebras over a local DG-Artin ring
Quiver representations and Gorenstein-projective modules
Full text linkWe consider a finite acyclic quiver Q and a quasi-Frobenius ring
R. We then characterise Gorenstein-projective modules over the path algebra
RQ in terms of the corresponding quiver representations over R,
generalizing the work of X.-H. Luo and P. Zhang to the case of not necessarily
finitely generated Q-modules. The proofs are based on Model
Category Theory. In particular we endow the category Rep(Q,
R) of quiver representations over R with a cofibrantly generated model
structure, and we recover the stable category of Gorenstein-projective
R-modules as the homotopy category
Ho(Rep(Q,R))
Formal deformation theory in left-proper model categories
No full textWe develop the notion of deformation of a morphism in a left-proper model category. As an application we provide a geomet-ric/homotopic description of deformations of commutative (non-positively) graded differential algebras over a local DG-Artin ring
Formality conjecture for minimal surfaces of Kodaira dimension 0
Full text linkLet be a polystable sheaf on a smooth minimal projective surface of Kodaira dimension 0. Then the differential graded (DG) Lie algebra of derived endomorphisms of is formal. The proof is based on the study of equivariant minimal models of DG Lie algebras equipped with a cyclic structure of degree 2 which is non-degenerate in cohomology, and does not rely (even for K3 surfaces) on previous results on the same subject
Formality conjecture for minimal surfaces of Kodaira dimension 0
Full text linkLet F be a polystable sheaf on a smooth minimal projective surface of Kodaira dimension 0. Then the differential graded (DG) Lie algebra RHom(F, F) of derived endomorphisms of F is formal. The proof is based on the study of equivariant L-infinity minimal models of DG Lie algebras equipped with a cyclic structure of degree 2 which is non-degenerate in cohomology, and does not rely (even for K3 surfaces) on previous results on the same subject
DEFORMATIONS OF POLYSTABLE SHEAVES ON SURFACES: QUADRATICITY IMPLIES FORMALITY
Full text linkWe study relations between the quadraticity of the Kuranishi family of a coherent sheaf on a complex projective scheme and the formality of the DG-Lie algebra of its derived endomorphisms. In particular, we prove that for a polystable coherent sheaf of a smooth complex projective surface the DG-Lie algebra of derived endomorphisms is forif i
Deformations of polystable sheaves on surfaces: quadraticity implies formality
Full text linkWe study relations between the quadraticity of the Kuranishi family of a coherent sheaf on a complex projective scheme and the formality of the DG-Lie algebra of its derived endomorphisms. In particular, we prove that for a polystable coherent sheaf of a smooth complex projective surface the DG-Lie algebra of derived endomorphisms is formal if and only if the Kuranishi family is quadratic
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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