> We get those from the original (discrete) topology, I assume? Yep! > ... is this construction related to the cofinite topology, then? I’m not sure, it’s so

> We get those from the original (discrete) topology, I assume? Yep! > ... is this construction related to the cofinite topology, then? I’m not sure, it’s sort of only cofinite “at infinity”? One place you see the cofinite topology appear is in algebraic geometry. The Zariski topology of a (connected) one-dimensional algebraic variety is the same as the cofinite topology. Glad I could help!