Uploaded April 2021 | Updated September 2026, 2 weeks ago

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This lecture is part of an online course on algebraic topology.

We define the fundamental group, calculate it for some easy examples (vector spaces and spheres), and give a couple of applications (R^2 is not homeomorphic to R^3, the Brouwer fixedpoint theorem).

For the other lectures in the course see youtube.com/playlist?list=PL8yHsr3EFj52yxQGxQoxwOtjIEtxE2BWx