3 papers
math.GM2023
A geometric view on planar graphs and its application to coloring
Henning Wunderlich
While planar graphs are flat from a topological viewpoint, we observe that they are not from a geometric one. We prove that every planar graph can be embedded into a surface consis…
math.FA2020
Characterization of Fréchet Spaces and Application to Hausdorff MNC
Henning Wunderlich
In this short note, we give a characterization of Fréchet spaces via properties of their metric. This allows us to prove that the Hausdorff measure of noncompactness (MNC), defined…
math.FA2019
On a characterization of spaces satisfying open mapping and equivalent theorems
Henning Wunderlich
For classes of topological vector spaces, we analyze under which conditions open-mapping, continuous-inverse, and closed-graph properties are equivalent. Here, closure under quotie…