A Breakthrough in Graph Theory - Numberphile

A counterexample to Hedetniemi's conjecture - featuring Erica Klarreich. Get 3 months of Audible for just $6.95 a month. Visit https://www.audible.com/numberphile or text "numberphile" to 500 500 More links & stuff in full description below ↓↓↓ Read Erica Klarreich's Quanta article on this subject: https://www.quantamagazine.org/mathem... And visit her website: http://www.ericaklarreich.com/ Yaroslav Shitov's breakthrough paper: https://arxiv.org/abs/1905.02167 Thanks to Stephen Hedetniemi for providing us with photos and pages from his original dissertation. Some more graph theory on Numberphile... Four Color Maps:    • The Four Color Map Theorem - Numberphile   An Unsolved Problem:    • A Colorful Unsolved Problem - Numberphile   Planar Graphs:    • Planar Graphs - Numberphile   Perfect Graphs:    • Perfect Graphs - Numberphile   Friends and Strangers:    • Friends and Strangers Theorem - Numberphile   River Crossings:    • River Crossings (and Alcuin Numbers) - Num...   Numberphile is supported by the Mathematical Sciences Research Institute (MSRI): http://bit.ly/MSRINumberphile We are also supported by Science Sandbox, a Simons Foundation initiative dedicated to engaging everyone with the process of science. https://www.simonsfoundation.org/outr... And support from Math For America - https://www.mathforamerica.org/ NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook:   / numberphile   Numberphile tweets:   / numberphile   Subscribe: http://bit.ly/Numberphile_Sub Videos by Brady Haran Patreon:   / numberphile   Numberphile T-Shirts: https://teespring.com/stores/numberphile Brady's videos subreddit:   / bradyharan   Brady's latest videos across all channels: http://www.bradyharanblog.com/ Sign up for (occasional) emails: http://eepurl.com/YdjL9