Séminaire - Juin
Le séminaire aura lieu un mercredi par mois de 14h à 15h à l'Institut Henri Poincaré à Paris. Pour télécharger l'affiche du mois: juin.pdf.
- 18/06/2025 - Richard Schwartz (Brown University)
salle Olga Ladyjenskaïa (ex-salle 01)
Titre: The
optimal paper Moebius band
Resumé: If
the number \(L\) is large you can
take a \(1 \times L\) rectangular strip, smoothly twist it in space, and
glue the ends together so as to make an embedded paper Moebius band. If
\(L\) is too small this is impossible. In this talk I will explain why
\(L > \sqrt{3}\) is a necessary and sufficient condition for the
existence of a smoothly embedded paper Moebius band. This is the
solution to the 1977 conjecture of B. Halpern and C. Weaver. I will
also explain why a sequence of \(L\)-minimizing examples must converge to
an equilateral triangle.