Topological comparison theorems for Bredon motivic cohomology

We prove equivariant versions of the Beilinson-Lichtenbaum conjecture for Bredon motivic cohomology of smooth complex and real varieties with an action of the group of order two. This identifies equivariant motivic and topological invariants in a large range of degrees.Comment: Corrected indices in main theorem and a few minor changes. To appear, Transactions AM

The K-theory of toric varieties in positive characteristic

We show that if X is a toric scheme over a regular ring containing a field then the direct limit of the K-groups of X taken over any infinite sequence of nontrivial dilations is homotopy invariant. This theorem was known in characteristic 0. The affine case of our result was conjectured by Gubeladze.Comment: Companion paper to arXiv:1106.138

Semi-topologization in motivic homotopy theory and applications

We study the semi-topologization functor of Friedlander-Walker from the perspective of motivic homotopy theory. We construct a triangulated endo-functor on the stable motivic homotopy category \mathcal{SH}(\C), which we call \emph{homotopy semi-topologization}. As applications, we discuss the representability of several semi-topological cohomology theories in \mathcal{SH}(\C), a construction of a semi-topological analogue of algebraic cobordism, and a construction of Atiyah-Hirzebruch type spectral sequences for this theory.Comment: v1: 41 pages; v2: 39 pages. The 'idempotence' part of v1 deleted, with some minor revision; v3: 24 pages. Largely rewritten and compactified. A variation of this version is accepted to appear in Algebraic & Geometric Topolog

Hodge filtered complex bordism

We construct Hodge filtered cohomology groups for complex manifolds that combine the topological information of generalized cohomology theories with geometric data of Hodge filtered holomorphic forms. This theory provides a natural generalization of Deligne cohomology. For smooth complex algebraic varieties, we show that the theory satisfies a projective bundle formula and \A^1-homotopy invariance. Moreover, we obtain transfer maps along projective morphisms.Comment: minor revision; final version accepted for publication by the Journal of Topolog