We all love eating pizza, but we don’t love so much using a fork and a knife for that. The problem is that the moment we pick up a slice of pizza with our hand, it tends to flop over and dangles from our fingers. Luckily, we have a solution: we just need to fold the slice along the bisection (making the shape of an U), that way the slice of pizza won’t bend down. Behind this apparently simple trick lies a remarkable mathematical result about the curvature of surfaces. This result was published in 1827 by Carl Friedrich Gauss and says that curvature is an intrinsic property of a surface, independent of its isometric embedding in Euclidean space. A consequence of this is that a 2-dimensional living being on a surface can measure the curvature of his land by just measuring angles and distances. Gauss found this result so outstanding that he named it by “Theorema Egregium” (latin for “remarkable theorem”). In this talk we’ll explain the historial context and the importance of this theorem, as well as show some surprising applications as, for example, its relation with our way of eating pizza.

Disclaimer: pizza won’t be served during the talk.