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Register a new userOn mixed-$omega$-sheaves
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Authors
Osamu Fujino
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We introduce the notion of mixed-$omega$-sheaves and use it for the study of a relative version of Fujitas freeness conjecture.
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We give a new simple proof of boundedness of the family of semistable sheaves with fixed numerical invariants on a fixed smooth projective variety. In characteristic zero our method gives a quick proof of Bogomolovs inequality for semistable sheaves on a smooth projective variety of any dimension $ge 2$ without using any restriction theorems.
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We conjecture that any perverse sheaf on a compact aspherical Kahler manifold has non-negative Euler characteristic. This extends the Singer-Hopf conjecture in the Kahler setting. We verify the stronger conjecture when the manifold X has non-positive holomorphic bisectional curvature. We also show that the conjecture holds when X is projective and in possession of a faithful semi-simple rigid local system. The first result is proved by expressing the Euler characteristic as an intersection number involving the characteristic cycle, and then using the curvature conditions to deduce non-negativity. For the second result, we have that the local system underlies a complex variation of Hodge structure. We then deduce the desired inequality from the curvature properties of the image of the period map.
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We formulate a few conjectures on some hypothetical coherent sheaves on the stacks of arithmetic local Langlands parameters, including their roles played in the local-global compatibility in the Langlands program. We survey some known results as evidences of these conjectures.
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