Tropical coordinates on the space of persistence barcodes

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Abstract/Contents

Abstract
In the last two decades applied topologists have developed numerous methods for `measuring' and building combinatorial representations of the shape of the data. The most famous example of the former is persistent homology. This adaptation of classical homology assigns a barcode, i.e. a collection of intervals with endpoints on the real line, to a finite metric space. Unfortunately, barcodes are not well-adapted for use by practitioners in machine learning tasks. In this dissertation, I identify classes of max-plus polynomials and tropical rational functions that can be used as coordinates on the space of barcodes. All of these are stable with respect to standard distance functions (bottleneck distance, Wasserstein distances) used on the barcode space. I demonstrate how these coordinates can be used by combining persistent homology with SVM to classify numbers from the MNIST dataset. In order to identify functions on the barcode space, I find generators for the semirings of tropical polynomials, max-plus polynomials and tropical rational functions invariant under the action of the symmetric group. The fundamental theorem of ordinary symmetric polynomials has an equivalent in the tropical and max-plus semirings. There are interesting differences if we consider the tropical polynomial semiring with nr variables that come in n blocks of r variables each and are permuted by the symmetric group. As opposed to the ordinary polynomial case, the semiring of r-symmetric tropical polynomials is not finitely generated, but the semiring of r-symmetric tropical rational functions is.

Description

Type of resource text
Form electronic; electronic resource; remote
Extent 1 online resource.
Publication date 2016
Issuance monographic
Language English

Creators/Contributors

Associated with Kališnik Verovšek, Sara
Associated with Stanford University, Department of Mathematics.
Primary advisor Carlsson, G. (Gunnar), 1952-
Thesis advisor Carlsson, G. (Gunnar), 1952-
Thesis advisor Brumfiel, Gregory W
Thesis advisor Kerckhoff, Steve
Advisor Brumfiel, Gregory W
Advisor Kerckhoff, Steve

Subjects

Genre Theses

Bibliographic information

Statement of responsibility Sara Kališnik Verovšek.
Note Submitted to the Department of Mathematics.
Thesis Thesis (Ph.D.)--Stanford University, 2016.
Location electronic resource

Access conditions

Copyright
© 2016 by Sara Kalisnik Verovsek
License
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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