In this post we will look at the correspondence between torsion in cohomology of finite CW-complexes and torsion in their K-theory. The title could just as well have been “a use case for Atiyah-Hirzebruch spectral sequence” as this will be our primary tool.
Continue reading “A note on torsion in K-theory”Equivalent ways to define topology
In every course in basic topology one learns the standard way to define a topology on a set 
, how to induce it from a basis, ambient space or a collection of functions into or out of the set. There are however other ways to associate a topology to a given set which may come up in practice. Here is a list of some of the once I have come across, let me know if you think there should be more elements to the list, as I am not an expert on this stuff.