3,538 research outputs found

    All flat manifolds are cusps of hyperbolic orbifolds

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    We show that all closed flat n-manifolds are diffeomorphic to a cusp cross-section in a finite volume hyperbolic (n+1)-orbifold.Comment: Published by Algebraic and Geometric Topology at http://www.maths.warwick.ac.uk/agt/AGTVol2/agt-2-13.abs.htm

    The Dynastinae (Coleoptera: Scarabaeidae) of the Cayman Islands (West Indies), with descriptions of Tomarus adoceteus, new species (Pentodontini) and Caymania nitidissima, new genus and species (Phileurini)

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    The five genera and eight species of dynastine scarabs occurring in the Cayman Islands in the West Indies are reviewed. Two new, endemic species are described from Little Cayman, with supporting illustrations: Tomarus adoceteus Ratcliffe and Cave (Pentodontini), new species, and Caymania nitidissima Ratcliffe and Cave (Phileurini), new genus and species

    On the geometric boundaries of hyperbolic 4-manifolds

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    We provide, for hyperbolic and flat 3-manifolds, obstructions to bounding hyperbolic 4-manifolds, thus resolving in the negative a question of Farrell and Zdravkovska.Comment: 8 pages. Published copy, also available at http://www.maths.warwick.ac.uk/gt/GTVol4/paper5.abs.htm

    Closed Quasi-Fuchsian Surfaces In Hyperbolic Knot Complements

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    We show that every hyperbolic knot complement contains a closed quasi-Fuchsian surface.Comment: 69 pages, 27 figures. Made small changes suggested by refere

    ‘Ethnic group’, the state and the politics of representation

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    The assertion, even if only by implication, that ‘ethnic group’ categories represent ‘real’ tangible entities, indeed identities, is commonplace not only in the realms of political and policy discourse but also amongst contemporary social scientists. This paper, following Brubaker (2002), questions this position in a number of key respects: of these three issues will dominate the discussion that follows. First, there is an interrogation of the proposition that those to whom the categories/labels refer constitute sociologically meaningful ‘groups’ as distinct from (mere) human collectivities. Secondly, there is the question of how these categories emerge, i.e. exactly what series of events, negotiations and contestations lie behind their construction and social acceptance. Thirdly, and as a corollary to the latter point, we explore the process of reification that leads to these categories being seen to represent ‘real things in the world’ (ibid.)

    Collisions at infinity in hyperbolic manifolds

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    For a complete, finite volume real hyperbolic n-manifold M, we investigate the map between homology of the cusps of M and the homology of MM. Our main result provides a proof of a result required in a recent paper of Frigerio, Lafont, and Sisto

    Peaks in the Hartle-Hawking Wave Function from Sums over Topologies

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    Recent developments in ``Einstein Dehn filling'' allow the construction of infinitely many Einstein manifolds that have different topologies but are geometrically close to each other. Using these results, we show that for many spatial topologies, the Hartle-Hawking wave function for a spacetime with a negative cosmological constant develops sharp peaks at certain calculable geometries. The peaks we find are all centered on spatial metrics of constant negative curvature, suggesting a new mechanism for obtaining local homogeneity in quantum cosmology.Comment: 16 pages,LaTeX, no figures; v2: some changes coming from revision of a math reference: wave function peaks sharp but not infinite; v3: added paragraph in intro on interpretation of wave functio

    Gluon polarization in the proton

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    We combine heavy-quark renormalization group arguments with our understanding of the nucleon's wavefunction to deduce a bound on the gluon polarization Delta g in the proton. The bound is consistent with the values extracted from spin experiments at COMPASS and RHIC.Comment: 4 page

    New species of \u3ci\u3eOrizabus\u3c/i\u3e Fairmaire (Coleoptera: Scarabaeidae: Dynastinae: Pentodontini) from Mexico and Guatemala, with a revised key and checklist of the species in the genus

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    Five new species of Orizabus Fairmaire from Mexico and Guatemala are described, illustrated, and compared with other Orizabus species: O. amalgamatus Ratcliffe and Cave, O. delgadoi Ratcliffe and Cave, O. epithecus Ratcliffe and Cave, O. mezclus Ratcliffe and Cave, and O. thomasi Ratcliffe and Cave. An identification key and a checklist of the species in the genus Orizabus are provided
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