Lecture 1.1: Topological Spaces, 'practical' examples

I will cover the topology of the real line and the definition of continuous.

[notlessgrossman]

Using cartoons to convey the essential intuition is pretty cool.

[LaureanoLuna]

It seems you take the set containing just the empty set -{0}- for the empty set itself. Furthermore, what you have to prove is not that the union (intersection) of open intervals is an open interval but that the union (intersetcion) of open sets is an open set.

[ninosawbrzostowiecki]

4:23 those fumes are taking their toll.

[xoppa]

why is an infinite union of open intervals an open interval by assumption?
 you defined open sets on R as unions of open intervals of R. presumably this is finite unions of R

[englishwithsuhaib]

Hello please can you help us to learn topology