AlgTop1: One-dimensional objects
This is the first lecture of this beginner's course in Algebraic Topology (after the Introduction). In it we introduce the two basic one-dimensional objects: the line and circle. The latter has quite a few different manifestations: as a usual Euclidean circle, as the projective line of one-dimensional subspaces of a two-dimensional space, as a polygon, or as a space of orbits of a translation group on the line.
This course is given by Assoc Prof N J WIldberger of the School of Mathematics and Statistics at UNSW. See also his series on Rational Trigonometry (WildTrig), Foundations of Mathematics (MathFoundations), Universal Hyperbolic Geometry, as well as Linear Algebra (WildLinAlg) under YouTube user: njwildberger at https://www.youtube.com/user/njwildberger?ob=0