Stage 3 Introductory Topology

Introductory Topology:
Topology is an extension of geometry and built on set theory, it's about continuity. There is a joke that topologists are those who cannot distinguish between a doughnut and a coffee or tea cup. Wikipedia has a [.gif] to demonstrate this. You may have studied open sets, open neighbourhood, interior, closure, boundary, basis, continuity, compactness and connectedness etc. in the analysis course, move on to homemorphism, homotopy and fundamental group.

As in abstract algebra and analysis, several selected books or notes cover more than enough. You may leave a few sections to study at the next stage.