Owens, B. and Strle, S. (2022) Disoriented homology and double branched covers. Canadian Journal of Mathematics, (doi: 10.4153/S0008414X22000591) (Early Online Publication)
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Abstract
This paper provides a convenient and practical method to compute the homology and intersection pairing of a branched double cover of the 4-ball. To projections of links in the 3-ball, and to projections of surfaces in the 4-ball into the boundary sphere, we associate a sequence of homology groups, called the disoriented homology. We show that the disoriented homology is isomorphic to the homology of the double branched cover of the link or surface. We define a pairing on the first disoriented homology group of a surface and show that this is equal to the intersection pairing of the branched cover. These results generalize work of Gordon and Litherland, for embedded surfaces in the 3-sphere, to arbitrary surfaces in the 4-ball. We also give a generalization of the signature formula of Gordon-Litherland to the general setting. Our results are underpinned by a theorem describing a handle decomposition of the branched double cover of a codimension-2 submanifold in the n-ball, which generalizes previous results of Akbulut-Kirby and others.
Item Type: | Articles |
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Status: | Early Online Publication |
Refereed: | Yes |
Glasgow Author(s) Enlighten ID: | Owens, Professor Brendan |
Authors: | Owens, B., and Strle, S. |
College/School: | College of Science and Engineering > School of Mathematics and Statistics > Mathematics |
Journal Name: | Canadian Journal of Mathematics |
Publisher: | Cambridge University Press |
ISSN: | 0008-414X |
ISSN (Online): | 1496-4279 |
Published Online: | 11 November 2022 |
Copyright Holders: | Copyright © 2022 Canadian Mathematical Society |
First Published: | First published in Canadian Journal of Mathematics 2022 |
Publisher Policy: | Reproduced in accordance with the copyright policy of the publisher |
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