1,720,962 research outputs found

    Enriched Reedy categories

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    We define the notion of an enriched Reedy category and show that if A is a C-Reedy category for some symmetric monoidal model category C and M is a C-model category, the category of C-functors and C-natural transformations from A to M is again a model category.This research was partially conducted during the period the author was employed by the Clay Mathematics Institute as a Liftoff Fellow

    Uniqueness of BP⟨n⟩

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    Fix a prime number p and an integer n≥ 0. We prove that if a p-complete spectrum X satisfying a mild finiteness condition has the same mod p cohomology as BP⟨ n⟩ as a module over the Steenrod algebra, then X is weak homotopy equivalent to the p-completion of BP⟨ n⟩.The first author was supported by an ARC Discovery grant. The second author was partially supported by the DFG through SFB-1085, and thanks the Australian National University for hosting him while this research was conducted

    The cyclic bar construction on A∞H-spaces

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    We set up a general framework for enriching a category A over a symmetric monoidal category C using a non-Σ operad P in C. To do this we require A to come with a functor U : A → Δ Σ+ to the category of noncommutative sets. By viewing the simplicial

    R(3,10) <= 41

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    We improve the upper bound on the Ramsey number R(3,10) from 42 to 41. Hence R(3,10) is equal to 40 or 41

    Noncommutative ring spectra

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2006.Includes bibliographical references (p. 87-91).Let A be an Ax ring spectrum. We give an explicit construction of topological Hochschild homology and cohomology of A using the Stasheff associahedra and another family of polyhedra called cyclohedra. Using this construction we can then study how THH(A) varies over the moduli space of AO structures on A, a problem which seems largely intractable using strictly associative replacements of A. We study how topological Hochschild cohomology of any 2-periodic Morava K-theory varies over the moduli space of AO structures and show that in the generic case, when a certain matrix describing the multiplication is invertible, the result is the corresponding Morava E-theory. If this matrix is not invertible, the result is some extension of Morava E-theory, and exactly which extension we get depends on the AO structure. To make sense of our constructions, we first set up a general framework for enriching a subcategory of the category of noncommutative sets over a category C using products of the objects of a non-E operad P in C. By viewing the simplicial category as a subcategory of the category of noncommutative sets in two different ways, we obtain two generalizations of simplicial objects.(cont.) For the operad given by the Stasheff associahedra we obtain a model for the 2-sided bar construction in the first case and the cyclic bar and cobar construction in the second case. Using either the associahedra or the cyclohedra in place of the geometric simplices we can define the geometric realization of these objects.by Vigleik Angeltveit.Ph.D

    HOPF ALGEBRA STRUCTURE ON TOPOLOGICAL HOCHSCHILD HOMOLOGY

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    The topological Hochschild homology THH(R) of a commutative S-algebra (E∞ ring spectrum) R naturally has the structure of a Hopf algebra over R, in the homotopy category. We show that under a flatness assumption this makes the Bökstedt spectral sequence converging to the mod p homology of THH(R) into a Hopf algebra spectral sequence. We then apply this additional structure to study some interesting examples, including the commutative S-algebras ku, ko, tmf, ju and j, and to calculate the homotopy groups of THH(ku) and THH(ko) after smashing with suitable finite complexes. This is part of a program to make systematic computations of the algebraic K-theory of S-algebras, using topological cyclic homology

    Graded Tambara Functors

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    We define the notion of an RO(G)\mathcal{RO}(G)-graded Tambara functor and prove that any GG-spectrum with norm multiplication gives rise to such an RO(G)\mathcal{RO}(G)-graded Tambara functor.Comment: 25 pages; elaborated on the description of graded Tambara functors and clarified some of the category theory. Added more detailed reference

    Graded Tambara functors

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    We define the notion of an -graded Tambara functor and prove that any G-spectrum with norm multiplication gives rise to such an -graded Tambara functor.This project was started after Discovery Grant No. DP120101399 from the Australian Research Council paid for the second author to visit the first author. We would also like to thank MSRI for hosting both of us during the Algebraic Topology program where some of this work was carried out. This material is based on work partially supported by the National Science Foundation under Grant No. 0932078 000 while the authors were in residence at the Mathematical Sciences Research Institute in Berkeley, California, during the Spring 2014 semester. The second author was also partially supported by National Science Foundation grant number DMS-1710534
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