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1. • CommentRowNumber1.
   • CommentAuthorRichard Williamson
   • CommentTimeJun 7th 2017
   • PermaLink
   Author: Richard Williamson
   Format: MarkdownItexAt [[linking number]], I added a diagrammatic/combinatorial proof that the linking number is an integer, and hence that there must be an even number of crossings between a pair of components of a link. It is surprisingly hard to find a diagrammatic proof: the typical argument is geometric, using something like the Jordan curve theorem. I stumbled across the argument I have added yesterday and thought it was rather nice, so decided to add it here before I forget it!

   At linking number, I added a diagrammatic/combinatorial proof that the linking number is an integer, and hence that there must be an even number of crossings between a pair of components of a link. It is surprisingly hard to find a diagrammatic proof: the typical argument is geometric, using something like the Jordan curve theorem. I stumbled across the argument I have added yesterday and thought it was rather nice, so decided to add it here before I forget it!