Notes for AKT-170117-2/0:13:00

Roland At 13:18 there is the statement that the width of a knot diagram is Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \mathcal{O}(\sqrt{n})} where n is the number of crossings. I think this is a consequence of the more general planar-graph result called the Planar Separator Theorem, or rather the edge version: https://en.wikipedia.org/wiki/Planar_separator_theorem Here's a link to the relevant article: http://www.sciencedirect.com/science/article/pii/S0196677483710138?via%3Dihub