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dc.contributor.authorKilbane, James
dc.date.accessioned2019-01-21T16:43:56Z
dc.date.available2019-01-21T16:43:56Z
dc.date.issued2019-01-31
dc.date.submitted2018-07-20
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/288272
dc.description.abstractThe central idea in this thesis is the introduction of a new isometric invariant of a Banach space. This is Property AI-I. A Banach space has Property AI-I if whenever a finite metric space almost-isometrically embeds into the space, it isometrically embeds. To study this property we introduce two further properties that can be thought of as finite metric variants of Dvoretzky's Theorem and Krivine's Theorem. We say that a Banach space satisfies the Finite Isometric Dvoretzky Property (FIDP) if it contains every finite subset of $\ell_2$ isometrically. We say that a Banach space has the Finite Isometric Krivine Property (FIKP) if whenever $\ell_p$ is finitely representable in the space then it contains every subset of $\ell_p$ isometrically. We show that every infinite-dimensional Banach space \emph{nearly} has FIDP and every Banach space nearly has FIKP. We then use convexity arguments to demonstrate that not every Banach space has FIKP, and thus we can exhibit classes of Banach spaces that fail to have Property AI-I. The methods used break down when one attempts to prove that there is a Banach space without FIDP and we conjecture that every infinite-dimensional Banach space has Property FIDP.
dc.language.isoen
dc.rightsAttribution-ShareAlike 4.0 International (CC BY-SA 4.0)
dc.rights.urihttps://creativecommons.org/licenses/by-sa/4.0/
dc.subjectBanach Spaces
dc.subjectMetric Spaces
dc.subjectMetric Embeddings
dc.titleFinite Metric Subsets of Banach Spaces
dc.typeThesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnameDoctor of Philosophy (PhD)
dc.publisher.institutionUniversity of Cambridge
dc.publisher.departmentDPMMS
dc.date.updated2019-01-05T12:15:02Z
dc.identifier.doi10.17863/CAM.35589
dc.type.qualificationtitlePhD in Pure Maths and Math Statistics
cam.supervisorZsak, Andras
cam.thesis.fundingfalse


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Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)
Except where otherwise noted, this item's licence is described as Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)