Does anyone have any good reference to exercises concerning these topics? I would like to understand them better. Thank you.
the point is to understand complicated spaces in terms of simpler ones.
i.e. an interval is simpler than a circle but a circle i q quotient o an interval.
'a torus is moire complicated than a rectangle but a torus is a quotient of a rectangle,....
almost any space is a successive union of quotients of rectangles of various dimensions.