1,721,002 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The cobordism of Real manifolds and calculations with the Real Adams-Novikov spectral sequence.
No full textThe purpose of this dissertation is both geometric and algebraic. Geometrically, I identify the cobordism groups of Real manifolds, which are manifolds whose stable normal bundles have smooth antilinear actions by the group of two elements. I show that these cobordism groups are homotopy groups of known spectra. In the algebraic part of the dissertation. I give concrete calculations of elements in the Real Adams-Novikov spectral sequence. This is a new spectral sequence based on the Real cobordism spectrum, and has the potential to give new information about the stable homotopy groups of spheres. I formulate the notion of a spectral sequence of transfinite length, indexed over the Grothedieck group of the ordinal numbers, and construct a version of the chromatic spectral sequence in the form of a transfinite spectral sequence. Using this, I compute summands of the Real Adams-Novikov spectral sequence in Ext degrees 0 and 1. I also investigate relationships between the elements in Ext degree 0 and families of elements in the Adams spectral sequences for the sphere and the infinite real projective space.PhDMathematicsPure SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/130996/2/9825253.pd
Stable splittings of configuration spaces of surfaces and related mapping spaces.
No full textIn this thesis, we study the stable homotopy theory of mapping spaces whose domains are surfaces. Classical results inextricably link this topic with the study of configuration spaces of surfaces. The main result is a stable splitting of these mapping spaces when the target is a sphere; that is, a wedge decomposition in the stable homotopy category. While this type of result is akin in spirit to the splittings of O nSigmanX due to James (for n = 1) and Snaith (for all n), the method of proof and type of results differ. By specializing to the case of surfaces, we obtain exact information about the homotopy type of the stable summands of the decomposition. These turn out to be constructed from Brown-Gitler spectra using the multiplicative structure of these spectra. As a consequence, we derive a complete calculation of the Steenrod operations on the cohomology of the function spaces of based maps from surfaces to spheres.PhDMathematicsPure SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/124211/2/3122070.pd
Pseudo limits, biadjoints, and pseudo algebras: categorical foundations of conformal field theory
No full textIn this paper we develop categorical foundations needed for a rigorous approach to the definition of conformal field theory outlined by Graeme Segal. We discuss pseudo algebras over theories and 2-theories, their pseudo morphisms, bilimits, bicolimits, bi-adjoints, stacks, and related concepts. These 2-categorical concepts are used to describe the algebraic structure on the class of rigged surfaces. A rigged surface is a real, compact, not necessarily connected, two dimensional manifold with complex structure and analytically parametrized boundary components. This class admits algebraic operations of disjoint union and gluing as well as a unit given by the empty rigged surface. These operations satisfy axioms of commutivity, associativity, unitality, transitivity, distributivity, and unit cancellation up to coherence isomorphism. Furthermore, these coherence isomorphisms satisfy coherence diagrams. These operations, coherences, and their diagrams are neatly encoded as a pseudo algebra over the 2-theory of commutative monoids with cancellation . A conformal field theory is a morphism of stacks of such structures. This thesis begins with a review of 2-categorical concepts, Lawvere theories, and algebras over Lawvere theories. We prove that the 2-categories of small categories and small pseudo algebras over a theory admit weighted pseudo limits and weighted bicolimits. The 2-category of pseudo algebras over a theory is bi-equivalent to the 2-category of algebras over a 2-monad with pseudo morphisms. We prove that a pseudo functor admits a left bi-adjoint if and only if it admits certain bi-universal arrows. An application of this theorem implies that the forgetful functor for pseudo algebras admits a left bi-adjoint. We introduce stacks for Grothendieck topologies and prove that the traditional definition of stacks in terms of descent data is equivalent to our definition via bilimits. The final chapter contains a proof that the 2-category of pseudo algebras over a 2-theory admits weighted pseudo limits. This result is relevant to the definition of conformal field theory because bilimits are necessary to speak of stacks.PhDHigh energy physicsMathematicsPure SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/125077/2/3186628.pd
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
The values of the Milnor genus on smooth irreducible projective varieties over the complex numbers.
No full textThe Milnor genus of a complex manifold is a higher dimensional generalization of the Euler characteristic of a Riemannian surface. It encodes all of the structure of the complex cobordism ring pi*(MU) modulo direct sums and topological products of complex manifolds. We completely compute the set of values of the Milnor genus on smooth, irreducible projective varieties over C , and as a result are able to make significant progress on a classical question of Hirzebruch: Which complex cobordism classes are represented by smooth, irreducible projective varieties?PhDMathematicsPure SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/132601/2/9977185.pd
The mod 2 cohomology of some classifying spaces of compact lie groups.
No full textIn this thesis, the mod 2 cohomology of BG, where G is either the group SU(n)/( Z/2) or U(n)/(Z/2), is considered. For any n, we exhibit a cochain complex C, given explicitly in terms of generators and relations, whose cohomology is the E2 term of the Eilenberg-Moore spectral sequence converging to HZ/2*(BG). For certain values of n, namely n odd, n = 2 mod 4, n = 4, and n = 8, we are able to compute the cohomology of C, thus giving a description of the E2 term of the Eilenberg-Moore spectral sequence. For these same values of n, we show that the Eilenberg-Moore spectral sequence collapses; thus HZ/2*(BG) = H*C up to extensions.PhDMathematicsPure SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/132685/2/9977261.pd
Some completion theorems in algebraic topology.
No full textThis thesis explores several different notions of completion. In chapter 2, the representation of a finite category is defined as a generalization of the representation of a group, and it is shown that when X is a simplicial complex, and is the category whose objects are simplices of X and morphisms are face inclusions of X, that the homotopy classes of maps \lbrack X,\ BGL\sb{n}(\doubc)) are in bijective correspondence with natural isomorphism classes of functors from to the category of n-dimensional vector spaces and linear isomorphisms. Chapter 3 looks at maps from the classifying space B{\doubz}/p into various E\sb{\infty}-spaces Z. It is conjectured that the spectrum associated to the E\sb{\infty}-space Map(B{\doubz}/p, Z) has the same \pi\sb0 as the function spectrum F(B{\doubz}/p, E\sb{Z}) where E\sb{Z} is the function spectrum associated with the E\sb{\infty}-space Z, up to some completion. This is shown to be true for the case of stable homotopy, topological complex K-theory, and the algebraic K-theory of {\rm I\!F}\sb{q}, where q is a prime different than p. This chapter also extends a theorem of Mislin that \lbrack B{\doubz}/p, BG\rbrack\simeq\lbrack B{\doubz}/p, BG\sbsp{p}{\wedge}\rbrack where the ({-})\sbsp{p}{\wedge} denotes Bousfield-Kan p-completion from the case of G compact Lie to the case G an arithmetic group. In chapter 4, Bousfield-Kan's definition of R-completion of a space and Bousfield's R-completion of a group are used along with Lie algebra techniques to show that the free group on p generators is not {\doubz}\sb{(p)}-good in the sense of Bousfield-Kan.PhDMathematicsPure SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/131250/2/9840578.pd
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