Thom, Andreas

[["dc.bibliographiccitation.firstpage","251"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Geometric and Functional Analysis"],["dc.bibliographiccitation.lastpage","270"],["dc.bibliographiccitation.volume","18"],["dc.contributor.author","Thom, Andreas"],["dc.date.accessioned","2018-11-07T11:16:32Z"],["dc.date.available","2018-11-07T11:16:32Z"],["dc.date.issued","2008"],["dc.description.abstract","We study L-2-Betti numbers for von Neumann algebras, as defined by D. Shlyakhtenko and A. Connes in [CoS]. We give a definition of L-2-cohomology and show how the study of the first L-2-Betti number can be related to the study of derivations with values in a bi-module of affiliated operators. We show several results about the possibility of extending derivations from sub-algebras and about uniqueness of such extensions. In particular, we show that the first L-2-Betti number of a tracial von Neumann algebra coincides with the corresponding number for an arbitrary weakly dense sub-C -algebra. Along the way, we prove some results about the dimension function of modules over rings of affiliated operators which are of independent interest."],["dc.identifier.doi","10.1007/s00039-007-0634-7"],["dc.identifier.isi","000255413500010"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/54613"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Birkhauser Verlag Ag"],["dc.relation.issn","1016-443X"],["dc.title","L-2-cohomology for von Neumann algebras"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","295"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Journal of Operator Theory"],["dc.bibliographiccitation.lastpage","299"],["dc.bibliographiccitation.volume","61"],["dc.contributor.author","Thom, Andreas"],["dc.date.accessioned","2018-11-07T08:32:17Z"],["dc.date.available","2018-11-07T08:32:17Z"],["dc.date.issued","2009"],["dc.description.abstract","We study L-2-Betti numbers for von Neumann algebras, as defined by D. Shlyakhtenko and A. Connes in [2], in the presence of a bi-finite correspondence, and prove a proportionality formula."],["dc.identifier.isi","000266311800005"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/17304"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Theta Foundation"],["dc.relation.issn","0379-4024"],["dc.title","L-2-BETTI NUMBERS FOR SUBFACTORS"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","779"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Algebraic & Geometric Topology"],["dc.bibliographiccitation.lastpage","784"],["dc.bibliographiccitation.volume","7"],["dc.contributor.author","Schick, Thomas"],["dc.contributor.author","Thom, Andreas"],["dc.date.accessioned","2017-09-07T11:47:12Z"],["dc.date.available","2017-09-07T11:47:12Z"],["dc.date.issued","2007"],["dc.description.abstract","We give a counterexample to a conjecture of D H Gottlieb and prove a strengthened version of it. The conjecture says that a map from a finite CW–complex X to an aspherical CW–complex Y with non-zero Euler characteristic can have non-trivial degree (suitably defined) only if the centralizer of the image of the fundamental group of X is trivial. As a corollary we show that in the above situation all components of non-zero degree maps in the space of maps from X to Y are contractible. We use L 2 –Betti numbers and homological algebra over von Neumann algebras to prove the modified conjecture."],["dc.identifier.doi","10.2140/agt.2007.7.779"],["dc.identifier.gro","3146672"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/4462"],["dc.language.iso","en"],["dc.notes.intern","mathe"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.relation.issn","1472-2747"],["dc.title","On a conjecture of Gottlieb"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","6447"],["dc.bibliographiccitation.issue","9"],["dc.bibliographiccitation.journal","Transactions of the American Mathematical Society"],["dc.bibliographiccitation.lastpage","6462"],["dc.bibliographiccitation.volume","371"],["dc.contributor.author","Bradford, Henry"],["dc.contributor.author","Thom, Andreas"],["dc.date.accessioned","2020-12-10T18:16:05Z"],["dc.date.available","2020-12-10T18:16:05Z"],["dc.date.issued","2019"],["dc.identifier.doi","10.1090/tran/2019-371-09"],["dc.identifier.eissn","1088-6850"],["dc.identifier.issn","0002-9947"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/75043"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.title","Short laws for finite groups and residual finiteness growth"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1155"],["dc.bibliographiccitation.issue","8"],["dc.bibliographiccitation.journal","Communications on Pure and Applied Mathematics"],["dc.bibliographiccitation.lastpage","1171"],["dc.bibliographiccitation.volume","61"],["dc.contributor.author","Thom, Andreas"],["dc.date.accessioned","2018-11-07T11:12:20Z"],["dc.date.available","2018-11-07T11:12:20Z"],["dc.date.issued","2008"],["dc.description.abstract","We prove the algebraic eigenvalue conjecture of J. Dodziuk, P. Linnell, V. Mathai, T. Schick, and S. Yates (see [2]) for sofic groups. Moreover, we give restrictions on the spectral measure of elements in the integral group ring. Finally, we define integer operators and prove a quantization of the operator norm below 2. To the knowledge of the author, there is no group known that is not sofic. (c) 2007 Wiley Periodicals, Inc."],["dc.identifier.doi","10.1002/cpa.20217"],["dc.identifier.isi","000256890600005"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/53640"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","John Wiley & Sons Inc"],["dc.relation.issn","0010-3640"],["dc.title","Sofic groups and diophantine approximation"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","227"],["dc.bibliographiccitation.lastpage","347"],["dc.contributor.author","Bunke, Ulrich"],["dc.contributor.author","Schick, Thomas"],["dc.contributor.author","Spitzweck, Markus"],["dc.contributor.author","Thom, Andreas"],["dc.contributor.editor","Cortiñas, Guillermo"],["dc.contributor.editor","Cuntz, Joachim"],["dc.contributor.editor","Karoubi, Max"],["dc.contributor.editor","Nest, Ryszard"],["dc.contributor.editor","Weibel, Charles A."],["dc.date.accessioned","2017-09-07T11:43:06Z"],["dc.date.available","2017-09-07T11:43:06Z"],["dc.date.issued","2008"],["dc.description.abstract","We extend Pontrjagin duality from topological abelian groups to certain locally compact group stacks. To this end we develop a sheaf theory on the big site of topological spaces S in order to prove that the sheaves ExtiShAbS(G,T), i = 1, 2, vanish, where G is the sheaf represented by a locally compact abelian group and T is the circle. As an application of the theory we interpret topological T-duality of principal Tn-bundles in terms of Pontrjagin duality of abelian group stacks."],["dc.identifier.doi","10.4171/060-1/10"],["dc.identifier.gro","3146659"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/4447"],["dc.language.iso","en"],["dc.notes.intern","mathe"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.publisher","European Mathematical Society"],["dc.publisher.place","Zürich"],["dc.relation.eisbn","978-3-03719-560-4"],["dc.relation.isbn","978-3-03719-060-9"],["dc.relation.ispartof","$K$-theory and noncommutative geometry"],["dc.title","Duality for topological abelian group stacks and ehBduality"],["dc.type","book_chapter"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","747"],["dc.bibliographiccitation.journal","Journal of the London Mathematical Society"],["dc.bibliographiccitation.lastpage","773"],["dc.bibliographiccitation.volume","81"],["dc.contributor.author","Sauer, Roman"],["dc.contributor.author","Thom, Andreas"],["dc.date.accessioned","2018-11-07T08:42:52Z"],["dc.date.available","2018-11-07T08:42:52Z"],["dc.date.issued","2010"],["dc.description.abstract","We construct a spectral sequence for L-2-type cohomology groups of discrete measured groupoids. Based on the spectral sequence, we prove the Hopf-Singer conjecture for aspherical manifolds with poly-surface fundamental groups. More generally, we obtain a permanence result for the Hopf-Singer conjecture under taking fiber bundles whose base space is an aspherical manifold with poly-surface fundamental group. As further sample applications of the spectral sequence, we obtain new vanishing theorems and explicit computations of L-2-Betti numbers of groups and manifolds and obstructions to the existence of normal subrelations in measured equivalence relations."],["dc.description.sponsorship","DFG [SA 1661/1-1]; Max-Planck-Institute in Bonn"],["dc.identifier.doi","10.1112/jlms/jdq017"],["dc.identifier.isi","000278819000014"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/19808"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Oxford Univ Press"],["dc.relation.issn","0024-6107"],["dc.title","A spectral sequence to compute L-2-Betti numbers of groups and groupoids"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","271"],["dc.bibliographiccitation.issue","5-6"],["dc.bibliographiccitation.journal","Comptes Rendus Mathematique"],["dc.bibliographiccitation.lastpage","276"],["dc.bibliographiccitation.volume","347"],["dc.contributor.author","Collins, Benoit"],["dc.contributor.author","Haertel, Johannes"],["dc.contributor.author","Thom, Andreas"],["dc.date.accessioned","2018-11-07T08:31:55Z"],["dc.date.available","2018-11-07T08:31:55Z"],["dc.date.issued","2009"],["dc.description.abstract","We compute the Hochschild homology of the free orthogonal quantum group A(0)(n). We show that it satisfies Poincare duality and should be considered to be a 3-dimensional object. We then use recent results of R. Vergnioux to derive results about the l(2)-homology of A(0)(n) and estimates on the free entropy dimension of its set of generators. In particular, we show that the l(2) Betti-numbers of A(0)(n) all vanish and that the free entropy dimension is less than 1. To cite this article: B. Collins et al., C. R. Acad. Sci. Paris, Ser. I 347 (2009). (C) 2009 Academie des sciences. Published by Elsevier Masson SAS. All rights, reserved."],["dc.description.sponsorship","NSERC; ANR; JSPS; DFG [534, 1493]; CRC"],["dc.identifier.doi","10.1016/j.crma.2009.01.021"],["dc.identifier.isi","000264581300011"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/17226"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier France-editions Scientifiques Medicales Elsevier"],["dc.relation.issn","1631-073X"],["dc.title","Homology of free quantum groups"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1717"],["dc.bibliographiccitation.issue","15"],["dc.bibliographiccitation.journal","Planta Medica"],["dc.bibliographiccitation.lastpage","1723"],["dc.bibliographiccitation.volume","76"],["dc.contributor.author","Vouffo, Bertin"],["dc.contributor.author","Dongo, Etienne"],["dc.contributor.author","Facey, Petrea"],["dc.contributor.author","Thom, Andrea"],["dc.contributor.author","Sheldrick, George M."],["dc.contributor.author","Maier, Armin"],["dc.contributor.author","Fiebig, Heinz Herbert"],["dc.contributor.author","Laatsch, Hartmut"],["dc.date.accessioned","2018-11-07T08:38:56Z"],["dc.date.available","2018-11-07T08:38:56Z"],["dc.date.issued","2010"],["dc.description.abstract","From the methanol extract of the stem bark of the African tree Antiaris africana Engler, two new bioactive metabolites were isolated, namely, the alpha-amyrin derivative 1,beta,11 alpha-dihydroxy-3 beta-cinnamoyl-alpha-amyrin (antiarol cinnamate, 1) and a cardiac glycoside, 3 beta-O-(alpha-L-rhamnopyranosyl)-14 beta-hydroperoxy-5 beta-hydroxy-19-oxo-17 beta- card-20(22)-enolide (africanoside, 2a), together with the known compounds P-amyrin and its acetate, beta-sitosterol and its 3-O-beta-D-glucopyranoside, friedelin, ursolic and oleanolic acid, 19-norperiplogenin, strophanthidol, strophanthidinic acid, periplogenin (3a), 3-epiperiplogenin, strophanthidin (3b) and 3,3'-dimethoxy-4'-O-beta-D-xylopyronosyl-ellagic acid. Their structures were established on the basis of their spectroscopic data and by chemical methods, while 3a was additionally confirmed by X-ray crystal structure analysis. The aglycone moiety possessing a hydroperoxy group was found for the first time in cardenolides. Compounds 1 and 2a showed no activity against bacteria, fungi, and microalgae; however, the crude extract exhibited a high toxicity against Artemia sauna and a selective antitumor activity against human tumor cell lines. Africanoside (2a) effected a concentration-dependent inhibition of tumor cell growth with a mean IC(50) value of 5.3 nM."],["dc.description.sponsorship","German Academic Exchange Service (DAAD)"],["dc.identifier.doi","10.1055/s-0030-1249958"],["dc.identifier.isi","000283917300016"],["dc.identifier.pmid","20533166"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/18871"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Georg Thieme Verlag Kg"],["dc.relation.issn","0032-0943"],["dc.title","Antiarol Cinnamate and Africanoside, a Cinnamoyl Triterpene and a Hydroperoxy-cardenolide from the Stem Bark of Antiaris africana"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]