Ricardo Waibel

Ricardo Waibel

Rolling Knots

Written by Leon-Josip Dzojic, Matilde Sciortino, and Pirmin Kupffer In the year 1980 M. H. Freedman conjectured that every generic smooth knot in three dimensional Euclidean space has a tritangent plane, i.e., a plane tangent to three distinct points. However,…

Indra’s Pearls

Written by Alassane Diagne and Ayşegül Peközsoy Möbius transformations are functions of the form \(T\colon \mathbb{C}\rightarrow\mathbb{C},\ T(z) = \frac{az+b}{cz+d}\) with \(a\), \(b\), \(c\), \(d\) complex numbers. We often associate the mapping \(T\) with the matrix \(T=\begin{pmatrix}a&b\\ c&d\end{pmatrix}\). If you look…

Planimeters

Written by Aaron Osburg Imagine you are planning your birthday party which will take place in Heidelberg Castle. You have a lot of friends, so you are not quite sure if the inner courtyard of the castle provides enough space…