2,168 research outputs found

    {\Gamma}-species, quotients, and graph enumeration

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    The theory of {\Gamma}-species is developed to allow species-theoretic study of quotient structures in a categorically rigorous fashion. This new approach is then applied to two graph-enumeration problems which were previously unsolved in the unlabeled case-bipartite blocks and general k-trees.Comment: 84 pages, 10 figures, dissertatio

    {\Gamma}-species and the enumeration of k-trees

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    We study the class of graphs known as k-trees through the lens of Joyal's theory of combinatorial species (and an equivariant extension known as 'Γ\Gamma-species' which incorporates data about 'structural' group actions). This culminates in a system of recursive functional equations giving the generating function for unlabeled k-trees which allows for fast, efficient computation of their numbers. Enumerations up to k = 10 and n = 30 (for a k-tree with (n+k-1) vertices) are included in tables, and Sage code for the general computation is included in an appendix.Comment: 26 pages; includes Python cod

    What lessons does the CRA offer the insurance industry?

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    Community Reinvestment Act of 1977 ; Insurance industry

    MSSM Dark Matter Without Prejudice

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    Recently we examined a large number of points in a 19-dimensional parameter subspace of the CP-conserving MSSM with Minimal Flavor Violation. We determined whether each of these points satisfied existing theoretical, experimental, and observational constraints. Here we discuss the properties of the parameter space points allowed by existing data that are relevant for dark matter searches.Comment: 4 pages, 3 figs; talk given at SUSY0

    Discrete-vortex model for the symmetric-vortex flow on cones

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    A relatively simple but accurate potential flow model was developed for studying the symmetric vortex flow on cones. The model is a modified version of the model first developed by Bryson, in which discrete vortices and straight-line feeding sheets were used to represent the flow field. It differs, however, in the zero-force condition used to position the vortices and determine their circulation strengths. The Bryson model imposed the condition that the net force on the feeding sheets and discrete vortices must be zero. The proposed model satisfies this zero-force condition by having the vortices move as free vortices, at a velocity equal to at the local crossflow velocity at their centers. When the free-vortex assumption is made, a solution is obtained in the form of two nonlinear algebraic equations that relate the vortex center coordinates and vortex strengths to the cone angle and angle of attack. The vortex center locations calculated using the model are in good agreement with experimental values. The cone normal forces as well as center locations are in good agreement with the vortex cloud method of calculating symmetric flow fields

    A METHOD FOR COMPUTING THE EFFECT OF AN ADDITIONAL OBSERVATION ON A PREVIOUS LEAST-SQUARES ESTIMATE

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    A data reduction method for computing effect of additional observation on previous least-squares estimate

    Low-speed investigation of effects of vertical tails on the static stability characteristics of a canard-bomber configuration having a very thin wing and a slender elliptical fuselage

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    Effect of vertical tails on low speed static stability characteristics of canard-bomber configuration with very thin wing and slender elliptical fuselag
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