This is Barbara Jung's talk "What is ... the the origin of elliptic functions?" at the "What is ...?" seminar. The talk was given on Friday, November 26, 12:30pm at the BMS Loft at Urania.
Elliptic functions are double-periodic meromorphic functions on C, that means basically f(a+ib) = f( (a+n) + i(b+m) ) for all a,b \in R, n,m \in Z. So they define a function on a torus. But what has this to do with an ellipse? To find the answer, we go on a journey to the origins of Riemann surfaces in the times of Euler and Lagrange and see the theory beautifully arising from the observation of integrals over some simple curves we already know from school.
For more "What is ...?" seminar videos, visit math.fu-berlin.de/w/Math/WhatIsSeminar