WebMar 10, 2024 · Short description: Generalization of vector bundles. In mathematics, especially in algebraic geometry and the theory of complex manifolds, coherent sheaves are a class of sheaves closely linked to the geometric properties of the underlying space. The definition of coherent sheaves is made with reference to a sheaf of rings that …
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Broadly speaking, coherent sheaf cohomology can be viewed as a tool for producing functions with specified properties; sections of line bundles or of more general sheaves can be viewed as generalized functions. In complex analytic geometry, coherent sheaf cohomology also plays a foundational role. See more In mathematics, especially in algebraic geometry and the theory of complex manifolds, coherent sheaves are a class of sheaves closely linked to the geometric properties of the underlying space. The definition of … See more On an arbitrary ringed space quasi-coherent sheaves do not necessarily form an abelian category. On the other hand, the quasi-coherent sheaves on any scheme form … See more Let $${\displaystyle f:X\to Y}$$ be a morphism of ringed spaces (for example, a morphism of schemes). If $${\displaystyle {\mathcal {F}}}$$ is a quasi-coherent sheaf on $${\displaystyle Y}$$, then the inverse image $${\displaystyle {\mathcal {O}}_{X}}$$-module … See more For a morphism of schemes $${\displaystyle X\to Y}$$, let $${\displaystyle \Delta :X\to X\times _{Y}X}$$ be the diagonal morphism, which is a closed immersion if $${\displaystyle X}$$ is separated over $${\displaystyle Y}$$. Let See more A quasi-coherent sheaf on a ringed space $${\displaystyle (X,{\mathcal {O}}_{X})}$$ is a sheaf $${\displaystyle {\mathcal {F}}}$$ of $${\displaystyle {\mathcal {O}}_{X}}$$-modules which … See more • An $${\displaystyle {\mathcal {O}}_{X}}$$-module $${\displaystyle {\mathcal {F}}}$$ on a ringed space $${\displaystyle X}$$ is called locally free of finite rank, or a vector bundle, if every point in $${\displaystyle X}$$ has an open neighborhood $${\displaystyle U}$$ such … See more An important feature of coherent sheaves $${\displaystyle {\mathcal {F}}}$$ is that the properties of $${\displaystyle {\mathcal {F}}}$$ at a point $${\displaystyle x}$$ control the behavior of See more WebWe also say that a sheaf of rings Fon X is coherent if it is coherent when considered as an F-module (i.e. if it satis es the above de nition for the ringed space (X;F)). In what follows in this section, all sheaves will be O X-modules for a … pump style advanced
Quasi-coherent sheaf on - Mathematics Stack Exchange
Webcoherent if and only if for every open a ne U = SpecA ˆX, Fj U = M~. If in addition X is Noetherian then Fis coherent if and only if M is a nitely generated A-module. This is … WebBasic invariants of a coherent sheaf: rank and degree De nition 3. Let Fbe a coherent sheaf. The rank of Fis de ned as the rank of the locally free sheaf (F=torsion) when we … WebFeb 22, 2024 · The very next proposition states the converse, that is a closed immersion Y → X gives rise to a sheaf of ideals (namely the kernel) whose closed subspace is isomorphic to Y. Explicitly, Proposition 2.2.24: Let f: Y → X be a closed immersion of ringed spaces, J: = kerf#, and Z = V(J). pumps \u0026 irrigation maryborough