{"title":"Positive scalar curvature and homology cobordism invariants","authors":"Hokuto Konno, Masaki Taniguchi","doi":"10.1112/topo.12299","DOIUrl":"10.1112/topo.12299","url":null,"abstract":"<p>We give an obstruction to positive scalar curvature metrics on 4-manifolds with the homology <math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>S</mi>\u0000 <mn>1</mn>\u0000 </msup>\u0000 <mo>×</mo>\u0000 <msup>\u0000 <mi>S</mi>\u0000 <mn>3</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$S^{1} times S^{3}$</annotation>\u0000 </semantics></math> described in terms of homology cobordism invariants from Seiberg–Witten theory. The main tool of the proof is a relative Bauer–Furuta-type invariant on a periodic-end 4-manifold.</p>","PeriodicalId":56114,"journal":{"name":"Journal of Topology","volume":"16 2","pages":"679-719"},"PeriodicalIF":1.1,"publicationDate":"2023-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43346472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A relative version of the Turaev–Viro invariants and the volume of hyperbolic polyhedral 3-manifolds","authors":"Tian Yang","doi":"10.1112/topo.12300","DOIUrl":"10.1112/topo.12300","url":null,"abstract":"<p>We define a relative version of the Turaev–Viro invariants for an ideally triangulated compact 3-manifold with nonempty boundary and a coloring on the edges, generalizing the Turaev–Viro invariants [36] of the manifold. We also propose the volume conjecture for these invariants whose asymptotic behavior is related to the volume of the manifold in the hyperbolic polyhedral metric [22, 23] with singular locus of the edges and cone angles determined by the coloring, and prove the conjecture in the case that the cone angles are sufficiently small. This suggests an approach of solving the volume conjecture for the Turaev–Viro invariants proposed by Chen–Yang [8] for hyperbolic 3-manifolds with totally geodesic boundary.</p>","PeriodicalId":56114,"journal":{"name":"Journal of Topology","volume":"16 2","pages":"650-678"},"PeriodicalIF":1.1,"publicationDate":"2023-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1112/topo.12300","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44611329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Strong \u0000 \u0000 \u0000 A\u0000 1\u0000 \u0000 ${mathbb {A}}^1$\u0000 -invariance of \u0000 \u0000 \u0000 A\u0000 1\u0000 \u0000 ${mathbb {A}}^1$\u0000 -connected components of reductive algebraic groups","authors":"Chetan Balwe, Amit Hogadi, Anand Sawant","doi":"10.1112/topo.12298","DOIUrl":"10.1112/topo.12298","url":null,"abstract":"<p>We show that the sheaf of <math>\u0000 <semantics>\u0000 <msup>\u0000 <mi>A</mi>\u0000 <mn>1</mn>\u0000 </msup>\u0000 <annotation>${mathbb {A}}^1$</annotation>\u0000 </semantics></math>-connected components of a reductive algebraic group over a perfect field is strongly <math>\u0000 <semantics>\u0000 <msup>\u0000 <mi>A</mi>\u0000 <mn>1</mn>\u0000 </msup>\u0000 <annotation>${mathbb {A}}^1$</annotation>\u0000 </semantics></math>-invariant. As a consequence, torsors under such groups give rise to <math>\u0000 <semantics>\u0000 <msup>\u0000 <mi>A</mi>\u0000 <mn>1</mn>\u0000 </msup>\u0000 <annotation>${mathbb {A}}^1$</annotation>\u0000 </semantics></math>-fiber sequences. We also show that sections of <math>\u0000 <semantics>\u0000 <msup>\u0000 <mi>A</mi>\u0000 <mn>1</mn>\u0000 </msup>\u0000 <annotation>${mathbb {A}}^1$</annotation>\u0000 </semantics></math>-connected components of anisotropic, semisimple, simply connected algebraic groups over an arbitrary field agree with their <math>\u0000 <semantics>\u0000 <mi>R</mi>\u0000 <annotation>$R$</annotation>\u0000 </semantics></math>-equivalence classes, thereby removing the perfectness assumption in the previously known results about the characterization of isotropy in terms of affine homotopy invariance of Nisnevich locally trivial torsors.</p>","PeriodicalId":56114,"journal":{"name":"Journal of Topology","volume":"16 2","pages":"634-649"},"PeriodicalIF":1.1,"publicationDate":"2023-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44627731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}