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    A NOTE ON SYMMETRIC LINEAR FORMS AND TRACES ON THE RESTRICTED QUANTUM GROUP Ūq(sl(2))

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    In this paper we prove two results about SLF(Ūq), the algebra of symmetric linear forms on the restricted quantum group Ūq = Ūq (sl(2)). First, we express any trace on finite dimensional projective Ūq-modules as a linear combination in the basis of SLF(Ūq) constructed by Gainutdinov - Tipunin and also by Arike. In particular, this allows us to determine the symmetric linear form corresponding to the modified trace on projective Ūq-modules. Second, we give the explicit multiplication rules between symmetric linear forms in this basis

    A NOTE ON SYMMETRIC LINEAR FORMS AND TRACES ON THE RESTRICTED QUANTUM GROUP Ūq(sl(2))

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    In this paper we prove two results about SLF(Ūq), the algebra of symmetric linear forms on the restricted quantum group Ūq = Ūq (sl(2)). First, we express any trace on finite dimensional projective Ūq-modules as a linear combination in the basis of SLF(Ūq) constructed by Gainutdinov - Tipunin and also by Arike. In particular, this allows us to determine the symmetric linear form corresponding to the modified trace on projective Ūq-modules. Second, we give the explicit multiplication rules between symmetric linear forms in this basis

    Groupes de difféotopie, algèbres d'écheveaux et quantification combinatoire

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    The algebras L(g,n,H) have been introduced by Alekseev-Grosse-Schomerus and Buffenoir-Roche in the middle of the 1990's, in the program of combinatorial quantization of the moduli space of flat G-connections over the surface S(g,n) of genus g with n open disks removed. The Hopf algebra H, called gauge algebra, was originally the quantum group U_q(g), with g = Lie(G). In this thesis we apply these algebras L(g,n,H) to low-dimensional topology (mapping class groups and skein algebras of surfaces), under the assumption that H is a finite dimensional factorizable ribbon Hopf algebra which is not necessarily semisimple, the guiding example of such a Hopf algebra being the restricted quantum group associated to sl(2) (at a 2p-th root of unity).First, we construct from L(g,n,H) a projective representation of the mapping class groups of S(g,0)D and of S(g,0) (D being an open disk). We provide formulas for the representations of Dehn twists generating the mapping class group; in particular these formulas allow us to show that our representation is equivalent to the one constructed by Lyubashenko-Majid and Lyubashenko via categorical methods. For the torus S(1,0) with the restricted quantum group associated to sl(2) for the gauge algebra, we compute explicitly the representation of SL(2,Z) using a suitable basis of the representation space and we determine the structure of this representation.Second, we introduce a diagrammatic description of L(g,n,H) which enables us to define in a very natural way the Wilson loop map W. This maps associates an element of L(g,n,H) to any link in (S(g,n)D) x [0,1] which is framed, oriented and colored by H-modules. When the gauge algebra is the restricted quantum group associated to sl(2), we use W and the representations of L(g,n,H) to construct representations of the skein algebras S_q(S(g,n)). For the torus S(1,0) we explicitly study this representation.Les algèbres L(g,n,H) ont été introduites par Alekseev-Grosse-Schomerus et Buffenoir-Roche au milieu des années 1990, dans le cadre de la quantification combinatoire de l'espace de modules des G-connexions plates sur la surface S(g,n) de genre g avec n disques ouverts enlevés. L'algèbre de Hopf H, appelée algèbre de jauge, était à l'origine le groupe quantique U_q(g), avec g=Lie(G). Dans cette thèse nous appliquons les algèbres L(g,n,H) à la topologie en basses dimensions (groupe de difféotopie et algèbres d'écheveaux des surfaces), sous l'hypothèse que H est une algèbre de Hopf de dimension finie, factorisable et enrubannée mais pas nécessairement semi-simple, l'exemple phare d'une telle algèbre de Hopf étant le groupe quantique restreint associé à sl(2) (à une racine 2p-ième de l'unité). D'abord, nous construisons en utilisant L(g,n,H) une représentation projective des groupes de difféotopie de S(g,0)D et de S(g,0) (où D est un disque ouvert). Nous donnons des formules pour les représentations d'un ensemble de twists de Dehn qui engendre le groupe de difféotopie; en particulier ces formules nous permettent de montrer que notre représentation est équivalente à celle construite par Lyubashenko-Majid et Lyubashenko via des méthodes catégoriques. Pour le tore S(1,0) avec le groupe quantique restreint associé à sl(2) comme algèbre de jauge, nous calculons explicitement la représentation de SL(2,Z) en utilisant une base convenable de l'espace de représentation et nous en déterminons la structure.Ensuite, nous introduisons une description diagrammatique de L(g,n,H) qui nous permet de définir de façon très naturelle l'application boucle de Wilson W. Cette application associe un élément de L(g,n,H) à chaque entrelac dans (S(g,n)D) x [0,1] qui est parallélisé, orienté et colorié par des H-modules. Quand l'algèbre de jauge est le groupe quantique restreint associé à sl(2), nous utilisons W et les représentations de L(g,n,H) pour construire des représentations des algèbres d'écheveaux S_q(S(g,n)). Pour le tore S(1,0) nous étudions explicitement cette représentation

    Projective representations of mapping class groups in combinatorial quantization

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    Let Σg,n\Sigma_{g,n} be a compact oriented surface of genus gg with nn open disks removed. The graph algebra Lg,n(H)\mathcal{L}_{g,n}(H) was introduced by Alekseev--Grosse--Schomerus and Buffenoir--Roche and is a combinatorial quantization of the moduli space of flat connections on Σg,n\Sigma_{g,n}. We construct a projective representation of the mapping class group of Σg,n\Sigma_{g,n} using Lg,n(H)\mathcal{L}_{g,n}(H) and its subalgebra of invariant elements. Here we assume that the gauge Hopf algebra HH is finite-dimensional, factorizable and ribbon, but not necessarily semi-simple. We also give explicit formulas for the representation of the Dehn twists generating the mapping class group; in particular, we show that it is equivalent to a representation constructed by V. Lyubashenko using categorical methods.Comment: 32 pages; minor corrections and improvements; new section and new theorem adde

    Groupes de difféotopie, algèbres d'écheveaux et quantification combinatoire

    Get PDF
    The algebras L(g,n,H) have been introduced by Alekseev-Grosse-Schomerus and Buffenoir-Roche in the middle of the 1990's, in the program of combinatorial quantization of the moduli space of flat G-connections over the surface S(g,n) of genus g with n open disks removed. The Hopf algebra H, called gauge algebra, was originally the quantum group U_q(g), with g = Lie(G). In this thesis we apply these algebras L(g,n,H) to low-dimensional topology (mapping class groups and skein algebras of surfaces), under the assumption that H is a finite dimensional factorizable ribbon Hopf algebra which is not necessarily semisimple, the guiding example of such a Hopf algebra being the restricted quantum group associated to sl(2) (at a 2p-th root of unity).First, we construct from L(g,n,H) a projective representation of the mapping class groups of S(g,0)D and of S(g,0) (D being an open disk). We provide formulas for the representations of Dehn twists generating the mapping class group; in particular these formulas allow us to show that our representation is equivalent to the one constructed by Lyubashenko-Majid and Lyubashenko via categorical methods. For the torus S(1,0) with the restricted quantum group associated to sl(2) for the gauge algebra, we compute explicitly the representation of SL(2,Z) using a suitable basis of the representation space and we determine the structure of this representation.Second, we introduce a diagrammatic description of L(g,n,H) which enables us to define in a very natural way the Wilson loop map W. This maps associates an element of L(g,n,H) to any link in (S(g,n)D) x [0,1] which is framed, oriented and colored by H-modules. When the gauge algebra is the restricted quantum group associated to sl(2), we use W and the representations of L(g,n,H) to construct representations of the skein algebras S_q(S(g,n)). For the torus S(1,0) we explicitly study this representation.Les algèbres L(g,n,H) ont été introduites par Alekseev-Grosse-Schomerus et Buffenoir-Roche au milieu des années 1990, dans le cadre de la quantification combinatoire de l'espace de modules des G-connexions plates sur la surface S(g,n) de genre g avec n disques ouverts enlevés. L'algèbre de Hopf H, appelée algèbre de jauge, était à l'origine le groupe quantique U_q(g), avec g=Lie(G). Dans cette thèse nous appliquons les algèbres L(g,n,H) à la topologie en basses dimensions (groupe de difféotopie et algèbres d'écheveaux des surfaces), sous l'hypothèse que H est une algèbre de Hopf de dimension finie, factorisable et enrubannée mais pas nécessairement semi-simple, l'exemple phare d'une telle algèbre de Hopf étant le groupe quantique restreint associé à sl(2) (à une racine 2p-ième de l'unité). D'abord, nous construisons en utilisant L(g,n,H) une représentation projective des groupes de difféotopie de S(g,0)D et de S(g,0) (où D est un disque ouvert). Nous donnons des formules pour les représentations d'un ensemble de twists de Dehn qui engendre le groupe de difféotopie; en particulier ces formules nous permettent de montrer que notre représentation est équivalente à celle construite par Lyubashenko-Majid et Lyubashenko via des méthodes catégoriques. Pour le tore S(1,0) avec le groupe quantique restreint associé à sl(2) comme algèbre de jauge, nous calculons explicitement la représentation de SL(2,Z) en utilisant une base convenable de l'espace de représentation et nous en déterminons la structure.Ensuite, nous introduisons une description diagrammatique de L(g,n,H) qui nous permet de définir de façon très naturelle l'application boucle de Wilson W. Cette application associe un élément de L(g,n,H) à chaque entrelac dans (S(g,n)D) x [0,1] qui est parallélisé, orienté et colorié par des H-modules. Quand l'algèbre de jauge est le groupe quantique restreint associé à sl(2), nous utilisons W et les représentations de L(g,n,H) pour construire des représentations des algèbres d'écheveaux S_q(S(g,n)). Pour le tore S(1,0) nous étudions explicitement cette représentation

    A note on symmetric linear forms and traces on the restricted quantum group Uˉq(sl(2))\bar U_q(\mathfrak{sl}(2))

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    18 pages, corrected typos, added references, results unchangedWe prove two results about SLF(Uˉq)\text{SLF}(\bar U_q), the algebra of symmetric linear forms on the restricted quantum group Uˉq=Uˉq(sl(2))\bar U_q = \bar U_q(\mathfrak{sl}(2)). First, we express any trace on finite dimensional projective Uˉq\bar U_q-modules as a linear combination in the basis of SLF(Uˉq)\text{SLF}(\bar U_q) constructed by Gainutdinov - Tipunin and also by Arike. In particular, this allows us to determine the symmetric linear form corresponding to the modified trace on projective Uˉq\bar U_q-modules. Second, we give the explicit multiplication rules between symmetric linear forms in this basis

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

    A note on symmetric linear forms and traces on the restricted quantum group Uˉq(sl(2))\bar U_q(\mathfrak{sl}(2))

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    We prove two results about SLF(Uˉq)\text{SLF}(\bar U_q), the algebra of symmetric linear forms on the restricted quantum group Uˉq=Uˉq(sl(2))\bar U_q = \bar U_q(\mathfrak{sl}(2)). First, we express any trace on finite dimensional projective Uˉq\bar U_q-modules as a linear combination in the basis of SLF(Uˉq)\text{SLF}(\bar U_q) constructed by Gainutdinov - Tipunin and also by Arike. In particular, this allows us to determine the symmetric linear form corresponding to the modified trace on projective Uˉq\bar U_q-modules. Second, we give the explicit multiplication rules between symmetric linear forms in this basis.Comment: 20 pages, correction of a wrong argument in the proof of Theorem 5.1 (result unchanged). Final version, to appear in Osaka J. Mat
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