No Arabic abstract
In this paper we introduce an equivariant extension of the Chern-Simons form, associated to a path of connections on a bundle over a manifold M, to the free loop space LM, and show it determines an equivalence relation on the set of connections on a bundle. We use this to define a ring, loop differential K-theory of M, in much the same way that differential K-theory can be defined using the Chern-Simons form [SS]. We show loop differential K-theory yields a refinement of differential K-theory, and in particular incorporates holonomy information into its classes. Additionally, loop differential K-theory is shown to be strictly coarser than the Grothendieck group of bundles with connection up to gauge equivalence. Finally, we calculate loop differential K-theory of the circle.
We use the geometry of the space of fields for gauged supersymmetric mechanics to construct the twisted differential equivariant K-theory of a manifold with an action by a finite group.
We show that Mandells inverse $K$-theory functor is a categorically-enriched multifunctor. In particular, it preserves algebraic structures parametrized by operads. As applications, we describe how ring categories, bipermutative categories, braided ring categories, and $E_n$-monoidal categories arise as the images of inverse $K$-theory.
We establish an equivalence of homotopy theories between symmetric monoidal bicategories and connective spectra. For this, we develop the theory of $Gamma$-objects in 2-categories. In the course of the proof we establish strictfication results of independent interest for symmetric monoidal bicategories and for diagrams of 2-categories.
In this paper we explain how Morse theory for the Yang-Mills functional can be used to prove an analogue, for surface groups, of the Atiyah-Segal theorem. Classically, the Atiyah-Segal theorem relates the representation ring R(Gamma) of a compact Lie group $Gamma$ to the complex K-theory of the classifying space $BGamma$. For infinite discrete groups, it is necessary to take into account deformations of representations, and with this in mind we replace the representation ring by Carlssons deformation $K$--theory spectrum $K (Gamma)$ (the homotopy-theoretical analogue of $R(Gamma)$). Our main theorem provides an isomorphism in homotopy $K_*(pi_1 Sigma)isom K^{-*}(Sigma)$ for all compact, aspherical surfaces $Sigma$ and all $*>0$. Combining this result with work of Tyler Lawson, we obtain homotopy theoretical information about the stable moduli space of flat unitary connections over surfaces.
Using a construction closely related to Waldhausens $S_bullet$-construction, we produce a spectrum $K(mathbf{Var}_{/k})$ whose components model the Grothendieck ring of varieties (over a field $k$) $K_0 (mathbf{Var}_{/k})$. We then produce liftings of various motivic measures to spectrum-level maps, including maps into Waldhausens $K$-theory of spaces $A(ast)$ and to $K(mathbf{Q})$. We end with a conjecture relating $K(mathbf{Var}_{/k})$ and the doubly-iterated $K$-theory of the sphere spectrum.