Last year I posted a blog post where we looked at a way to use elementary homotopy theory to hang a picture on the wall in a stupid way. The task was to hang a picture on two nails in such a way that if we pull one of the nails out, the picture falls down. “That is stupid” I hear you say, but premise is as premise does, or something similar quoted from Forrest Gump....

Are there knots?

Something I have been looking into a bit lately, due to it sadly not being taught at my university is knot theory. This is something I have always known to be a part of topology, and have known to have interesting applications in physics, medicine, chemistry and more. So to rectify the situation I thought I would prove that knots exist. It was also nice to take a brake from all the higher category theory we have been looking into lately!...