What is...relative homology?

Goal. Explaining basic concepts of algebraic topology in an intuitive way. This time. What is...relative homology? Or: Calculations modulo subspaces. Disclaimer. Nobody is perfect, and I might have said something silly. If there is any doubt, then please check the references. Disclaimer. These videos are concerned with algebraic topology, and not general topology. (These two are not to be confused.) I assume that you know bits and pieces about general topology, but not too much, I hope. Slides. http://www.dtubbenhauer.com/youtube.html Website with exercises. http://www.dtubbenhauer.com/lecture-a... Relative homology. https://en.wikipedia.org/wiki/Relativ... https://math.stackexchange.com/questi... https://ncatlab.org/nlab/show/relativ... Short and long exact sequences. https://en.wikipedia.org/wiki/Exact_s... Pictures used. https://slideplayer.com/slide/11382479/ https://en.wikipedia.org/wiki/Exact_s... Hatcher’s book (I sometimes steal some pictures from there). https://pi.math.cornell.edu/~hatcher/... Always useful. https://en.wikipedia.org/wiki/Counter... Mathematica. #algebraictopology #topology #mathematics