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Non-Orientable Lagrangian Fillings of Legendrian Knots

Published online by Cambridge University Press:  27 September 2023

LINYI CHEN
Affiliation:
Google, Inc., 1021 Valley Street, Seattle, WA 98019, U.S.A. e-mail: chenlinyi1996@gmail.com
GRANT CRIDER-PHILLIPS
Affiliation:
University of Oregon, 1585 E 13th Ave, Eugene, OR 97403, U.S.A. e-mail: criderg@uoregon.edu
BRAEDEN REINOSO
Affiliation:
Boston College, Department of Mathematics, Maloney Hall Fifth Floor, 21 St Thomas More Road, Chestnut Hill, MA 02467, U.S.A. e-mail: reinosob@bc.edu
JOSHUA SABLOFF
Affiliation:
Haverford College, Department of Mathematics, 370 Lancaster Ave, Haverford, PA 19041, U.S.A. e-mail: jsabloff@haverford.edu
LEYU YAO
Affiliation:
University of Cambridge, Department of Applied Mathematics and Theoretical Physics, Wilberforce Road, Cambridge CB3 0WA. e-mail: ly339@cam.ac.uk

Abstract

We investigate when a Legendrian knot in the standard contact ${{\mathbb{R}}}^3$ has a non-orientable exact Lagrangian filling. We prove analogs of several results in the orientable setting, develop new combinatorial obstructions to fillability, and determine when several families of knots have such fillings. In particular, we completely determine when an alternating knot (and more generally a plus-adequate knot) is decomposably non-orientably fillable and classify the fillability of most torus and 3-strand pretzel knots. We also describe rigidity phenomena of decomposable non-orientable fillings, including finiteness of the possible normal Euler numbers of fillings and the minimisation of crosscap numbers of fillings, obtaining results which contrast in interesting ways with the smooth setting.

Type
Research Article
Copyright
© The Author(s), 2023. Published by Cambridge University Press on behalf of Cambridge Philosophical Society

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Footnotes

Partially supported by NSF grant DMS-1406093 during the preparation of this paper.

Partially supported by grants from Haverford College.

References

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