We show that the two piecewise flat surfaces with conical singularities conjectured by
E Calabi as extremal surfaces for the isosystolic problem in genus 3 are critical with
respect to some metric variations. The proof relies on a new approach to study
isosystolic extremal surfaces.
Keywords
systole, systolic inequality, extremal
surface, flat surface with conical singularities, Calabi
surface, calibration, Busemann function
Received: 4 March 2010
Revised: 26 June 2011
Accepted: 12 June 2011
Published: 3 August 2011
Proposed: Dmitri Burago
Seconded: Tobias H. Colding, Leonid Polterovich