11 citations · 21 across the 15 of their papers we have counts for
5 papers · 1 filter
Exotic Steiner Chains in Miquelian Möbius Planes
Norbert Hungerbühler, Gideon Villiger
In the Euclidean plane, two intersecting circles or two circles which are tangent to each other clearly do not carry a finite Steiner chain. However, in this paper we will show tha…
Congruent number elliptic curves with rank at least two
Lorenz Halbeisen, Norbert Hungerbühler
We give an infinite family of congruent number elliptic curves, each with rank at least two, which are related to integral solutions of .
Communicating harmonic pencils of lines
Norbert Hungerbühler, Clemens Pohle
Suppose there are harmonic pencils of lines given in the plane. We are interested in the question whether certain triples of these lines are concurrent or if triples of interse…
Resistors in dual networks
Martina Furrer, Norbert Hungerbühler, Simon Jantschgi
Let be a finite plane multigraph and its dual. Each edge of is interpreted as a resistor of resistance , and the dual edge is assigned the dual resistanc…
A Theorem of Fermat on Congruent Number Curves
Lorenz Halbeisen, Norbert Hungerbühler
A positive integer is called a congruent number if is the area of a right-angled triangle with three rational sides. Equivalently, is a congruent number if and only if…