K-theory invariance of -operator algebras associated with étale groupoids of strong subexponential growth
Are Austad
University of Oslo, NorwayEduard Ortega
NTNU – Norwegian University of Science and Technology, Trondheim, NorwayMathias Palmstrøm
NTNU – Norwegian University of Science and Technology, Trondheim, Norway

Abstract
We introduce the notion of (strong) subexponential growth for étale groupoids and study its basic properties. In particular, we show that the K-groups of the associated reduced groupoid -operator algebras are independent of whenever the groupoid has strong subexponential growth. Several examples are discussed. Most significantly, we apply classical tools from analytic number theory to exhibit an example of an étale groupoid associated with a shift of infinite type which has strong subexponential growth, but not polynomial.
Cite this article
Are Austad, Eduard Ortega, Mathias Palmstrøm, K-theory invariance of -operator algebras associated with étale groupoids of strong subexponential growth. Doc. Math. (2026), published online first
DOI 10.4171/DM/1066