A Blast from the Past, continued

Putting on My Top Hat

I warned you. Nostalgia is a terrible force. Could we but harness it, our energy problems would be solved. Ah, the good old days...

Topologies

Topology is a branch of mathematics concerned with whether or not two points are close together, and how this closeness is affected by mappings from one space to another. On what basis can we say that two point a and b are "close"?

A topology on X is a family of subsets that constitute the "open" subsets of X. The familiar op...