Classifying complex geodesics for the Carathéodory metric on low-dimensional Teichmüller spaces

It was recently shown that the Carathéodory and Teichmüller metrics on the Teichmüller space of a closed surface do not coincide. On the other hand, Kra earlier showed that the metrics coincide when restricted to a Teichmüller disk generated by a differential with no odd-order zeros. Our aim is to c...

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Main Authors: Gekhtman, D, Markovic, V
Format: Journal article
Language:English
Published: Springer 2020
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author Gekhtman, D
Markovic, V
author_facet Gekhtman, D
Markovic, V
author_sort Gekhtman, D
collection OXFORD
description It was recently shown that the Carathéodory and Teichmüller metrics on the Teichmüller space of a closed surface do not coincide. On the other hand, Kra earlier showed that the metrics coincide when restricted to a Teichmüller disk generated by a differential with no odd-order zeros. Our aim is to classify Teichmüller disks on which the two metrics agree, and we conjecture that the Carathéodory and Teichmüller metrics agree on a Teichmüller disk if and only if the Teichmüller disk is generated by a differential with no odd-order zeros. Using dynamical results of Minsky, Smillie, and Weiss, we show that it suffices to consider disks generated by Jenkins-Strebel differentials. We then prove a complex-analytic criterion characterizing Jenkins-Strebel differentials which generate disks on which the metrics coincide. Finally, we use this criterion to prove the conjecture for the Teichmüller spaces of the five-times punctured sphere and the twice-punctured torus. We also extend the result that the Carathéodory and Teichmüller metrics are different to the case of compact surfaces with punctures.
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spelling oxford-uuid:01dadee3-9ddb-4662-93af-6997a8c2416b2022-03-26T08:37:13ZClassifying complex geodesics for the Carathéodory metric on low-dimensional Teichmüller spacesJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:01dadee3-9ddb-4662-93af-6997a8c2416bEnglishSymplectic ElementsSpringer2020Gekhtman, DMarkovic, VIt was recently shown that the Carathéodory and Teichmüller metrics on the Teichmüller space of a closed surface do not coincide. On the other hand, Kra earlier showed that the metrics coincide when restricted to a Teichmüller disk generated by a differential with no odd-order zeros. Our aim is to classify Teichmüller disks on which the two metrics agree, and we conjecture that the Carathéodory and Teichmüller metrics agree on a Teichmüller disk if and only if the Teichmüller disk is generated by a differential with no odd-order zeros. Using dynamical results of Minsky, Smillie, and Weiss, we show that it suffices to consider disks generated by Jenkins-Strebel differentials. We then prove a complex-analytic criterion characterizing Jenkins-Strebel differentials which generate disks on which the metrics coincide. Finally, we use this criterion to prove the conjecture for the Teichmüller spaces of the five-times punctured sphere and the twice-punctured torus. We also extend the result that the Carathéodory and Teichmüller metrics are different to the case of compact surfaces with punctures.
spellingShingle Gekhtman, D
Markovic, V
Classifying complex geodesics for the Carathéodory metric on low-dimensional Teichmüller spaces
title Classifying complex geodesics for the Carathéodory metric on low-dimensional Teichmüller spaces
title_full Classifying complex geodesics for the Carathéodory metric on low-dimensional Teichmüller spaces
title_fullStr Classifying complex geodesics for the Carathéodory metric on low-dimensional Teichmüller spaces
title_full_unstemmed Classifying complex geodesics for the Carathéodory metric on low-dimensional Teichmüller spaces
title_short Classifying complex geodesics for the Carathéodory metric on low-dimensional Teichmüller spaces
title_sort classifying complex geodesics for the caratheodory metric on low dimensional teichmuller spaces
work_keys_str_mv AT gekhtmand classifyingcomplexgeodesicsforthecaratheodorymetriconlowdimensionalteichmullerspaces
AT markovicv classifyingcomplexgeodesicsforthecaratheodorymetriconlowdimensionalteichmullerspaces