Operations on Milnor-Witt K-theory

TL;DR

This paper develops a framework for understanding and generating operations between Milnor-Witt K-theory and other homotopy modules, providing explicit computations of these operations and their relations to related theories.

Contribution

It introduces new operations on Milnor-Witt K-theory, enabling explicit descriptions of all such operations and their connections to Milnor, Witt, and related K-theories.

Findings

Defined operations generating all operations in the graded, ring-structured case.

Explicitly computed the group of all operations between Milnor-Witt K-theories.

Connected operations on Milnor-Witt K-theory with those on Milnor and Witt K-theories.

Abstract

For all positive integers $n$ and all homotopy modules $M_*$, we define certain operations $\underline{\operatorname{K}}^{\operatorname{MW}}_n \rightarrow M_*$ and show that these generate the $M_*(k)$-module of all (in general non-additive) operations $\underline{\operatorname{K}}^{\operatorname{MW}}_n \rightarrow M_*$ in a suitable sense, if $M_*$ is $\mathbb{N}$-graded and has a ring structure. This also allows us to explicitly compute the abelian group $\operatorname{Op}(\underline{\operatorname{K}}^{\operatorname{MW}}_n,\underline{\operatorname{K}}^{\operatorname{MW}}_m)$ and all operations between related theories such as Milnor, Witt and Milnor-Witt K-theory.