{"title":"Amenable category and complexity","authors":"Pietro Capovilla, C. Loeh, M. Moraschini","doi":"10.2140/agt.2022.22.1417","DOIUrl":"https://doi.org/10.2140/agt.2022.22.1417","url":null,"abstract":"Amenable category is a variant of the Lusternik-Schnirelman category, based on covers by amenable open subsets. We study the monotonicity problem for degree-one maps and amenable category and the relation between amenable category and topological complexity.","PeriodicalId":50826,"journal":{"name":"Algebraic and Geometric Topology","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82171803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Homological polynomial coefficients and the twist number of alternating surface links","authors":"David A. Will","doi":"10.2140/agt.2022.22.3939","DOIUrl":"https://doi.org/10.2140/agt.2022.22.3939","url":null,"abstract":"For $D$ a reduced alternating surface link diagram, we bound the twist number of $D$ in terms of the coefficients of a polynomial invariant. To this end, we introduce a generalization of the homological Kauffman bracket defined by Krushkal. Combined with work of Futer, Kalfagianni, and Purcell, this yields a bound for the hyperbolic volume of a class of alternating surface links in terms of these coefficients.","PeriodicalId":50826,"journal":{"name":"Algebraic and Geometric Topology","volume":"43 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2020-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73289518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Scott Balchin, J. Greenlees, Luca Pol, J. Williamson
{"title":"Torsion models for tensor-triangulated categories: the one-step case","authors":"Scott Balchin, J. Greenlees, Luca Pol, J. Williamson","doi":"10.2140/agt.2022.22.2805","DOIUrl":"https://doi.org/10.2140/agt.2022.22.2805","url":null,"abstract":"Given a suitable stable monoidal model category $mathscr{C}$ and a specialization closed subset $V$ of its Balmer spectrum one can produce a Tate square for decomposing objects into the part supported over $V$ and the part supported over $V^c$ spliced with the Tate object. Using this one can show that $mathscr{C}$ is Quillen equivalent to a model built from the data of local torsion objects, and the splicing data lies in a rather rich category. As an application, we promote the torsion model for the homotopy category of rational circle-equivariant spectra from [16] to a Quillen equivalence. In addition, a close analysis of the one step case highlights important features needed for general torsion models which we will return to in future work.","PeriodicalId":50826,"journal":{"name":"Algebraic and Geometric Topology","volume":"118 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2020-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76004864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daniel Kasprowski, John Nicholson, Benjamin Matthias Ruppik
{"title":"Homotopy classification of 4–manifolds whose\u0000fundamental group is dihedral","authors":"Daniel Kasprowski, John Nicholson, Benjamin Matthias Ruppik","doi":"10.2140/agt.2022.22.2915","DOIUrl":"https://doi.org/10.2140/agt.2022.22.2915","url":null,"abstract":"We show that the homotopy type of an oriented Poincare 4-complex is determined by its quadratic 2-type provided its fundamental group is finite and has a dihedral Sylow 2-subgroup. This applies in the case of smooth oriented 4-manifolds whose fundamental group is a finite subgroup of SO(3), examples of which are elliptic surfaces with finite fundamental group.","PeriodicalId":50826,"journal":{"name":"Algebraic and Geometric Topology","volume":"33 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2020-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87826211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}