28,848 research outputs found

    Big qq-ample Line Bundles

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    A recent paper of Totaro develops a theory of qq-ample bundles in characteristic 0. Specifically, a line bundle LL on XX is qq-ample if for every coherent sheaf F\mathcal{F} on XX, there exists an integer m0m_0 such that mm0m\geq m_0 implies Hi(X,FO(mL))=0H^i(X,\mathcal{F}\otimes \mathcal{O}(mL))=0 for i>qi>q. We show that a line bundle LL on a complex projective scheme XX is qq-ample if and only if the restriction of LL to its augmented base locus is qq-ample. In particular, when XX is a variety and LL is big but fails to be qq-ample, then there exists a codimension 1 subscheme DD of XX such that the restriction of LL to DD is not qq-ample.Comment: 9 pages, 2 pdf figure

    Chip-firing groups of iterated cones

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    Let Γ\Gamma be a finite graph and let Γn\Gamma_n be the "nnth cone over Γ\Gamma" (i.e., the join of Γ\Gamma and the complete graph KnK_n). We study the asymptotic structure of the chip-firing group Pic0(Γn)\text{Pic}^0(\Gamma_n).Comment: 8 pages. v4: added Remark 1.

    A novel synthetic chemistry approach to linkage-specific ubiquitin conjugation.

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    Ubiquitination is of great importance as the post-translational modification of proteins with ubiquitin, or ubiquitin chains, facilitates a number of vital cellular processes. Herein we present a facile method of preparing various ubiquitin conjugates under mild conditions using michael acceptors based on dibromo-maleimides and dibromo-pyridazinediones

    Approximate Fixed Point Theorems in Banach Spaces with Applications in Game Theory

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    In this paper some new approximate fixed point theorems for multifunctions in Banach spaces are presented and a method is developed indicating how to use approximate fixed point theorems in proving the existence of approximate Nash equilibria for non-cooperative games.Nash equilibrium;noncooperative games

    Effects of suspended sediments on the development of eggs and larvae of striped bass and white perch

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    The possible ecological effects of suspended sediments are manifold. Briefly, suspended sediments may cause an increased surface for microorganism growth, fewer temperature fluctuations, chemical adsorption or absorption, blanketing, mechanical-abrasive actions, and light penetration reduction (Cairns, 1968). Sherk and Cronin (1970) have pointed out that the above effects have been little studied in the estuarine environment. The ecological effects of suspended sediments on fish eggs and larvae may be of prime importance t o the C and D Canal area, an important spawning and primary nursery area for a variety of estuary: e species (Johnson,1972). This section discusses the effects of suspended sediment on the eggs and larvae of striped bass and white perch
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