Friends and Strangers Theorem

A famous mathematical theorem explained with the help of Facebook, One Direction and a collection of Numberphile's Facebook followers.

Videos features Simon Pampena - https://twitter.com/mathemaniac

NOTE: Yes we should have used greater/equals symbols at around 5:15, but the meaning pretty clear and Brady and Simon live about 10,500 miles apart --- so not worth a re-shoot!

More on the theorem: http://en.wikipedia.org/wiki/Theorem_on_friends_and_strangers