A video of the lecture is available <a href="uploads/2020-03-13-174719.webm">here</a>. But I forgot to connect the microphone so the sound is a bit noisy.
<br><br>
Introduced the fundamental group of a space. Indicated why the fundamental group of the circle S<sup>1</sup> is isomorphic to the additive group of the integers <b>Z</b>. This isomorphism was used to define the winding number of an arbitrary map f:S<sup>1</sup> ---> S<sup>1</sup>.