Topology IV.b - homotopy theory

Homework/Semi-flipped teaching. Please read or watch the beginning of Section 4 about fibrations. This is the beginning of Video 12.1 (up to minute 13):

https://mediaspace.epfl.ch/media/Fibrations%2C+Lecture+11.1/0_k00xss90

Alternatively you can read pages 75-76 of the lecture notes. It starts with an explanation about the "dualization" of the notion of cofibrations, the actual definition via the HLP, a trivial example, and some historical insight. I will continue in class with the useful characterization 8.5.