Counterexamples to Proofs for Volumetric Parameterization of Topological Sweeps

Harmonic maps are important in generating parameterizations for various domains, particularly in two and three dimensions. General extensions of two-dimensional harmonic parameterizations for volumetric parameterizations are known to fail in a variety of contexts, though more specialized volumetric parameterizations have been proposed. This work provides and contextualizes a counterexample to various proposed proofs that employ harmonic maps to sweep a parameterization from a base surface, $\Gamma_0$, to the entire domain of a geometry that is homeomorphic to $\Gamma_0\times[0,1]$ or $\Gamma_0\times S^1$. While this does not negate the potential value of such topological sweep parameterizations, it does clarify that these swept parameterizations come with no inherent guarantees of bijectivity, as they may in two dimensions.