A Counterexample to Guillemin's Zollfrei Conjecture
arXiv:1302.2496 · doi:10.1142/S1793525313500143
Abstract
We construct Zollfrei Lorentzian metrics on every nontrivial orientable circle bundle over a orientable closed surface. Further we prove a weaker version of Guillemin's conjecture assuming global hyperbolicity of the universal cover.
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