57 research outputs found

    Higher order duality and toric embeddings

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    The notion of higher order dual varieties of a projective variety is a natural generalization of the classical notion of projective duality, introduced by Piene in 1983. In this paper we study higher order dual varieties of projective toric embeddings. We compute the degree of the second dual variety of a smooth toric threefold in geometric and combinatorial terms, and we classify smooth 2-jet spanned projective embeddings of smooth threefolds whose second dual variety has dimension less than expected. We also describe the tropicalization of the k-th dual variety of an equivariantly embedded (not necessarily normal) toric variety.Comment: Final version to appear in Annales de l'Institut Fourier. Deleted an unnecessary wrong statemen

    On Higher-order Duality in Nondifferentiable Minimax Fractional Programming

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    In this paper, we consider a nondifferentiable minimax fractional programming problem with continuously differentiable functions and formulated two types of higher-order dual models for such optimization problem.Weak, strong and strict converse duality theorems are derived under higherorder generalized invexity

    Higher order duality in multiobjective fractional programming with support functions

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    AbstractIn this paper a new class of higher order (F,ρ,σ)-type I functions for a multiobjective programming problem is introduced, which subsumes several known studied classes. Higher order Mond–Weir and Schaible type dual programs are formulated for a nondifferentiable multiobjective fractional programming problem where the objective functions and the constraints contain support functions of compact convex sets in Rn. Weak and strong duality results are studied in both the cases assuming the involved functions to be higher order (F,ρ,σ)-type I. A number of previously studied problems appear as special cases

    Higher Order Duality for Vector Optimization Problem over Cones Involving Support Functions

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    In this paper, we consider a vector optimization problem over cones involving support functions in  objective as well as constraints and associate a unified higher order dual to it.  Duality result have been established under the conditions of higher order cone convex and related functions.  A number of previously studied problems appear as special cases. Keywords: Vector optimization, Cones, Support Functions, Higher Order Duality

    Higher order wave-particle duality

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    The complementarity of single-photon's particle-like and wave-like behaviors can be described by the inequality D2+V2≀1D^2+V^2 \leq 1, with DD being the path distinguishability and VV being the fringe visibility. In this paper, we generalize this duality relation to multi-photon case, where two new concepts, higher order distinguishability and higher order fringe visibility, are introduced to quantify the higher order particle-like and wave-like behaviors of multi-photons.Comment: 5 pages, 1 figur

    Linear Toric Fibrations

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    These notes are based on three lectures given at the 2013 CIME/CIRM summer school. The purpose of this series of lectures is to introduce the notion of a toric fibration and to give its geometrical and combinatorial characterizations. Polarized toric varieties which are birationally equivalent to projective toric bundles are associated to a class of polytopes called Cayley polytopes. Their geometry and combinatorics have a fruitful interplay leading to fundamental insight in both directions. These notes will illustrate geometrical phenomena, in algebraic geometry and neighboring fields, which are characterized by a Cayley structure. Examples are projective duality of toric varieties and polyhedral adjunction theory

    Special Geometry and Twisted Moduli in Orbifold Theories with Continuous Wilson Lines

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    Target space duality symmetries, which acts on K\"ahler and continuous Wilson line moduli, of a ZN{\bf Z}_N (N=Ìž2N\not=2) 2-dimensional subspace of the moduli space of orbifold compactification are modified to include twisted moduli. These spaces described by the cosets SU(n,1)SU(n)×U(1)SU(n,1)\over SU(n)\times U(1) are specialspecial K\"ahler, a fact which is exploited in deriving the extension of tree level duality transformation to include higher orders of the twisted moduli. Also, restrictions on these higher order terms are derived.Comment: 13 page

    BFKL at Next-to-Next-to-Leading Order

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    We determine an approximate expression for the O(alpha_s^3) contribution chi_2 to the kernel of the BFKL equation, which includes all collinear and anticollinear singular contributions. This is derived using recent results on the relation between the GLAP and BFKL kernels (including running-coupling effects to all orders) and on small-x factorization schemes. We present the result in various schemes, relevant both for applications to the BFKL equation and to small-x evolution of parton distributions.Comment: 34 pages, 6 figures, TeX with harvmac. Various small typos corrects, in particular first term in eq D.3. Final version to be published in Nucl. Phys.
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