3 papers
math.HO2017
Roger Apéry: humour at the service of a free and original thinking on constructive mathematics
Henri Lombardi, Stefan Neuwirth
This article is an invitation to read a famous text of Roger Ap{é}ry, "Math{é}matique constructive", published in the book "Penser les math{é}matiques: s{é}minaire de philosophie e…
math.CO2001
The size of bipartite graphs with girth eight
Stefan Neuwirth
Reiman produced a quadratic inequality for the size of bipartite graphs of girth six. We get its counterpart for girth eight, a cubic inequality. It is optimal in as far as it admi…
math.CA2001
The Sidon constant of sets with three elements
Stefan Neuwirth
We solve an elementary extremal problem on trigonometric polynomials and obtain the exact value of the Sidon constant for sets with three elements {n0, n1, n2}: it is \sec(π/ 2n) f…