The Great Courses Plus free trial: http://ow.ly/RJw3301cRhU Cliff Stoll discusses a "Remarkable Theorem", Gaussian curvature and pizza. More links & stuff in full description below ↓↓↓ Postscript note from Cliff: "Cliff says he forgot to mention that at each point, he calls an outward going curve positive, and an inward going curve negative. He also neglected to say that saddle points have negative Gaussian curvature. Finally, he insists that the frozen pizza shown in this video is inferior to his wife's homemade pizza. But both have zero Gaussian curvature." Animation by Pete McPartlan. Support us on Patreon: http://www.patreon.com/numberphile NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook: http://www.facebook.com/numberphile Numberphile tweets: https://twitter.com/numberphile Subscribe: http://bit.ly/Numberphile_Sub Numberphile is supported by the Mathematical Sciences Research Institute (MSRI): http://bit.ly/MSRINumberphile Videos by Brady Haran Brady's videos subreddit: http://www.reddit.com/r/BradyHaran/ Brady's latest videos across all channels: http://www.bradyharanblog.com/ Sign up for (occasional) emails: http://eepurl.com/YdjL9 Numberphile T-Shirts: null Other merchandise: https://store.dftba.com/collections/numberphile