Fractional currents and Young geometric integration

Abstract

We introduce a class of flat currents with fractal properties, called fractional currents, which satisfy a compactness theorem and remain stable under pushforwards by H\"older continuous maps. In top dimension, fractional currents are the currents represented by functions belonging to a fractional Sobolev space. The space of $\alpha$-fractional currents is in duality with a class of cochains, $\alpha$-fractional charges, that extend both Whitney's flat cochains and $\alpha$-H\"older continuous forms. We construct a partially defined wedge product between fractional charges, enabling a generalization of the Young integral to arbitrary dimensions and codimensions. This helps us identify $\alpha$-fractional $m$-currents as metric currents of the snowflaked metric space $(\mathbb{R}^d, \mathrm{d}_{\mathrm{Eucl}}^{(m+\alpha)/(m+1)})$.