Quasiregular curves: Removability of singularities

Abstract

We prove a Painlevé theorem for bounded quasiregular curves in Euclidean spaces extending removability results for quasiregular mappings due to Iwaniec and Martin. The theorem is proved by extending a fundamental inequality for volume forms to calibrations and proving a Caccioppoli inequality for quasiregular curves. We also establish a qualitatively sharp removability theorem for quasiregular curves whose target is a Riemannian manifold with sectional curvature bounded from above and an injectivity radius lower bound. As an application, we extend a theorem of Bonk and Heinonen for quasiregular mappings to the setting of quasiregular curves: every non-constant quasiregular $\omega$-curve from ${\mathbb{R}}^n$ into $(N,\omega )$, where the bounded cohomology class of $\omega$ is in the bounded Künneth ideal, has infinite energy.

19 pages; added an injectivity radius lower bound assumption to the results about manifold-valued curves; contains a new section connecting injectivity radius lower bound and sectional curvature upper bound to isoperimetric inequalities up to small mass