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Dualizability in Low-Dimensional Higher Category Theory
These lecture notes form an expanded account of a course given at the Summer
School on Topology and Field Theories held at the Center for Mathematics at the
University of Notre Dame, Indiana during the Summer of 2012. A similar lecture
series was given in Hamburg in January 2013. The lecture notes are divided into
two parts.
The first part, consisting of the bulk of these notes, provides an expository
account of the author's joint work with Christopher Douglas and Noah Snyder on
dualizability in low-dimensional higher categories and the connection to
low-dimensional topology. The cobordism hypothesis provides bridge between
topology and algebra, establishing important connections between these two
fields. One example of this is the prediction that the -groupoid of
so-called `fully-dualizable' objects in any symmetric monoidal -category
inherits an O(n)-action. However the proof of the cobordism hypothesis outlined
by Lurie is elaborate and inductive. Many consequences of the cobordism
hypothesis, such as the precise form of this O(n)-action, remain mysterious.
The aim of these lectures is to explain how this O(n)-action emerges in a range
of low category numbers ().
The second part of these lecture notes focuses on the author's joint work
with Clark Barwick on the Unicity Theorem, as presented in arXiv:1112.0040.
This theorem and the accompanying machinery provide an axiomatization of the
theory of -categories and several tools for verifying these axioms.
The aim of this portion of the lectures is to provide an introduction to this
material.Comment: 65 pages, 8 figures. Lecture Note
A Generalized Contou-Carr\`ere Symbol and its Reciprocity Laws in Higher Dimensions
We generalize the theory of Contou-Carr\`ere symbols to higher dimensions. To
an -tuple , where
denotes a commutative algebra over a field , we associate an element
, compatible with the higher tame symbol for , and earlier constructions for , by Contou-Carr\`ere, and
by Osipov--Zhu. Our definition is based on the notion of \emph{higher
commutators} for central extensions of groups by spectra, thereby extending the
approach of Arbarello--de Concini--Kac and Anderson--Pablos Romo. Following
Beilinson--Bloch--Esnault for the case , we allow to be arbitrary, and
do not restrict to artinian . Previous work of the authors on Tate objects
in exact categories, and the index map in algebraic -theory is essential in
anchoring our approach to its predecessors. We also revisit categorical formal
completions, in the context of stable -categories. Using these tools,
we describe the higher Contou-Carr\`ere symbol as a composition of boundary
maps in algebraic -theory, and conclude the article by proving a version of
Parshin--Kato reciprocity for higher Contou-Carr\`ere symbols.Comment: 55 pages, introduction completely rewritte
Reporting categories in urine test strip analysis: Croatian survey and call for action
Introduction: In line with the national recommendations, Croatian medical laboratories report urine test strip qualitative analysis results using a categorized scale with defined number of categories. Since concentration ranges for measured analytes have not been provided by national professional authority, it is up to the laboratories to define their own categories. The aim of study was to assess the comparability of concentrations assigned to different categories used in reporting the results of dipstick urinalysis in Croatian laboratories.
Material and methods: A questionnaire was e-mailed to all Croatian medical laboratories (N = 195). They were asked to provide the number of categories and respective concentrations for each parameter. Data were described as numbers and percentages. Values above the upper reference range limit, which were assigned as normal and/or trace category, were considered as false negative.
Results: Response rate was 71% (139/195). Seventy percent (98/139) of laboratories report their results with either higher (77/98; 79%) or lower (2/98; 2%) number of categories, relative to the national recommendation, whereas 19/98 (19%) report their results as concentrations. Great heterogeneity of reporting categories was observed. Multiple categories were assigned to same concentrations and there was a large overlap of concentrations for most categories. Considerable proportion of laboratories reported false negative results for ketones (42%), leukocytes (30%) and glucose (21%).
Conclusions: The concentrations assigned to categories used to report the results of dipstick urinalysis are not comparable among Croatian medical laboratories. There is an urgent need for harmonization and standardization of reporting the results of urine dipstick analysis in Croatia
Capturing Goodwillie's Derivative
Recent work of Biedermann and R\"ondigs has translated Goodwillie's calculus
of functors into the language of model categories. Their work focuses on
symmetric multilinear functors and the derivative appears only briefly. In this
paper we focus on understanding the derivative as a right Quillen functor to a
new model category. This is directly analogous to the behaviour of Weiss's
derivative in orthogonal calculus. The immediate advantage of this new category
is that we obtain a streamlined and more informative proof that the
n-homogeneous functors are classified by spectra with an action of the
symmetric group on n objects. In a later paper we will use this new model
category to give a formal comparison between the orthogonal calculus and
Goodwillie's calculus of functors.Comment: Final version, to appear. Substantially shortened from earlier
version, with a significantly expanded introduction, new results and
examples. 27 page
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