5,679 research outputs found

    Generating functions for the universal Hall-Littlewood PP- and QQ-functions

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    Recently, P. Pragacz described the ordinary Hall-Littlewood PP-polynomials by means of push-forwards (Gysin maps) from flag bundles in the ordinary cohomology theory. Together with L. Darondeau, he also gave push-forward formulas (Gysin formulas) for all flag bundles of types AA, BB, CC and DD in the ordinary cohomology theory. In this paper, we introduce a generalization of the ordinary Hall-Littlewood PP- and QQ-polynomials, which we call the {\it universal ((factorial)) Hall-Littlewood PP- and QQ-functions}, and characterize them in terms of Gysin maps from flag bundles in the complex cobordism theory. We also generalize the (type AA) push-forward formula due to Darondeau-Pragacz to the complex cobordism theory. As an application of our Gysin formulas in complex cobordism, we give generating functions for the universal Hall-Littlewood PP- and QQ-functions and their factorial analogues. Using our generating functions, classical determinantal and Pfaffian formulas for Schur SS- and QQ-polynomials, and their KK-theoretic or factorial analogues can be obtained in a simple and unified manner.Comment: 46 pages, AMSLaTeX; Section 6 added, An error of the generating function for the universal factorial Hall-Littlewood PP-functions was correcte

    Excited Young diagrams and equivariant Schubert calculus

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    We describe the torus-equivariant cohomology ring of isotropic Grassmannians by using a localization map to the torus fixed points. We present two types of formulas for equivariant Schubert classes of these homogeneous spaces. The first formula involves combinatorial objects which we call ``excited Young diagrams'' and the second one is written in terms of factorial Schur QQ- or PP-functions. As an application, we give a Giambelli-type formula for the equivariant Schubert classes. We also give combinatorial and Pfaffian formulas for the multiplicity of a singular point in a Schubert variety.Comment: 29 page

    Experimental DML over digital repositories in Japan

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    In this paper the authors show an overview of Virtual Digital Mathematics Library in Japan (DML-JP), contents of which consist of metadata harvested from institutional repositories in Japan and digital repositories in the world. DML-JP is, in a sense, a subject specific repository which collaborate with various digital repositories. Beyond portal website, DML-JP provides subject-specific metadata through OAI-ORE. By the schema it is enabled that digital repositories can load the rich metadata which were added by mathematicians
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