### AlgTop2a: Homeomorphism and the group structure on a circle

This is the first video of the second lecture in this beginner's course on Algebraic Topology. We give the basic definition of homeomorphism between two topological spaces, and explain why the line and circle are not homeomorphic. Then we introduce the group structure on a circle, or in fact a general conic, in a novel way. This gives a gentle intro to the definition of a group. It also uses Pascal's theorem in an interesting way, so we give some background on projective geometry.NOTE: This entire series is now available in the full (hour long lectures), also at this channel under the playlist AlgTop (full lectures):http://www.youtube.com/playlist?list=PL6763F57A61FE6FE8&feature=view_all

Length:
10:02