Published online by Cambridge University Press: 06 November 2018
We construct a dynamically convex contact form on the three-sphere whose systolic ratio is arbitrarily close to 2. This example is related to a conjecture of Viterbo, whose validity would imply that the systolic ratio of a convex contact form does not exceed 1. We also construct, for every integer $n\geqslant 2$, a tight contact form with systolic ratio arbitrarily close to $n$ and with suitable bounds on the mean rotation number of all the closed orbits of the induced Reeb flow.
The research of A. Abbondandolo and B. Bramham is supported by the SFB/TRR 191 ‘Symplectic Structures in Geometry, Algebra and Dynamics’, funded by the Deutsche Forschungsgemeinschaft. P. A. S. Salomão is supported by the FAPESP grant 2016/25053-8 and the CNPq grant 306106/2016-7. U. L. Hryniewicz was supported by CNPq grant 309966/2016-7 and by the Humboldt Foundation; he also acknowledges the generous hospitality of the Mathematics Department of the Ruhr-Universität Bochum.