{"title":"Some Examples of Bicrossed Products with the Rapid Decay Property","authors":"Hua Wang","doi":"10.1007/s10468-024-10308-3","DOIUrl":"10.1007/s10468-024-10308-3","url":null,"abstract":"<div><p>We consider bicrossed products obtained by twisting compact semi-direct products by a suitable finite subgroup. We give a practical criterion for the rapid decay property and polynomial growth of the dual of such bicrossed products under a mild restriction. Using this theory, we construct concrete new examples of discrete quantum groups possessing the rapid decay property but not growing polynomially.</p></div>","PeriodicalId":50825,"journal":{"name":"Algebras and Representation Theory","volume":"28 1","pages":"101 - 123"},"PeriodicalIF":0.5,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143554030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Note on the Quantum Berezinian for the Double Yangian of the Lie Superalgebra (mathfrak {gl}_{m|n})","authors":"Lucia Bagnoli, Slaven Kožić","doi":"10.1007/s10468-024-10310-9","DOIUrl":"10.1007/s10468-024-10310-9","url":null,"abstract":"<div><p>In this note, we generalize the notion of quantum Berezinian to the double Yangian <span>(textrm{DY}(mathfrak {gl}_{m|n}))</span> of the Lie superalgebra <span>( mathfrak {gl}_{m|n} )</span>. We show that its coefficients form a family of algebraically independent topological generators of the center of <span>(textrm{DY}(mathfrak {gl}_{m|n}))</span>.</p></div>","PeriodicalId":50825,"journal":{"name":"Algebras and Representation Theory","volume":"28 1","pages":"143 - 155"},"PeriodicalIF":0.5,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143553920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Representations of the Super-Yangian of Type D(n, m)","authors":"A. I. Molev","doi":"10.1007/s10468-024-10304-7","DOIUrl":"10.1007/s10468-024-10304-7","url":null,"abstract":"<div><p>We consider the classification problem for finite-dimensional irreducible representations of the Yangians associated with the orthosymplectic Lie superalgebras <span>(mathfrak {osp}_{2n|2m})</span> with <span>(ngeqslant 2)</span>. We give necessary conditions for an irreducible highest weight representation to be finite-dimensional. We conjecture that these conditions are also sufficient and prove the conjecture for a class of representations with linear highest weights. The arguments are based on a new type of odd reflections for the Yangian associated with <span>(mathfrak {osp}_{2|2})</span>. In the Appendix, we construct an isomorphism between the Yangians associated with the Lie superalgebras <span>(mathfrak {osp}_{2|2})</span> and <span>(mathfrak {gl}_{1|2})</span>.</p></div>","PeriodicalId":50825,"journal":{"name":"Algebras and Representation Theory","volume":"28 1","pages":"25 - 45"},"PeriodicalIF":0.5,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10468-024-10304-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143553919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Extremal Weight Crystals Over Affine Lie Algebras of Infinite Rank","authors":"Taehyeok Heo","doi":"10.1007/s10468-024-10302-9","DOIUrl":"10.1007/s10468-024-10302-9","url":null,"abstract":"<div><p>We explain extremal weight crystals over affine Lie algebras of infinite rank using combinatorial models: a spinor model due to Kwon, and an infinite rank analogue of Kashiwara-Nakashima tableaux due to Lecouvey. In particular, we show that Lecouvey’s tableau model is isomorphic to an extremal weight crystal of level zero. Using these combinatorial models, we explain an algebra structure of the Grothendieck ring for a category consisting of some extremal weight crystals.</p></div>","PeriodicalId":50825,"journal":{"name":"Algebras and Representation Theory","volume":"28 1","pages":"1 - 24"},"PeriodicalIF":0.5,"publicationDate":"2024-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10468-024-10302-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143554018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Generalization of Quantum Lakshmibai-Seshadri Paths for an Arbitrary Weight","authors":"Takafumi Kouno, Satoshi Naito","doi":"10.1007/s10468-024-10298-2","DOIUrl":"10.1007/s10468-024-10298-2","url":null,"abstract":"<div><p>We construct an injective weight-preserving map (called the forgetful map) from the set of all admissible subsets in the quantum alcove model associated to an arbitrary weight. The image of this forgetful map can be explicitly described by introducing the notion of “interpolated quantum Lakshmibai-Seshadri (QLS for short) paths”, which can be thought of as a generalization of quantum Lakshmibai-Seshadri paths. As an application, we reformulate, in terms of interpolated QLS paths, an identity of Chevalley type for the graded characters of Demazure submodules of a level-zero extremal weight module over a quantum affine algebra, which is a representation-theoretic analog of the Chevalley formula for the torus-equivariant <i>K</i>-group of a semi-infinite flag manifold.</p></div>","PeriodicalId":50825,"journal":{"name":"Algebras and Representation Theory","volume":"27 6","pages":"2321 - 2353"},"PeriodicalIF":0.5,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10468-024-10298-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142994451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Flat Quasi-coherent Sheaves as Directed Colimits, and Quasi-coherent Cotorsion Periodicity","authors":"Leonid Positselski, Jan Š’ovíček","doi":"10.1007/s10468-024-10296-4","DOIUrl":"10.1007/s10468-024-10296-4","url":null,"abstract":"<div><p>We show that every flat quasi-coherent sheaf on a quasi-compact quasi-separated scheme is a directed colimit of locally countably presentable flat quasi-coherent sheaves. More generally, the same assertion holds for any countably quasi-compact, countably quasi-separated scheme. Moreover, for three categories of complexes of flat quasi-coherent sheaves, we show that all complexes in the category can be obtained as directed colimits of complexes of locally countably presentable flat quasi-coherent sheaves from the same category. In particular, on a quasi-compact semi-separated scheme, every flat quasi-coherent sheaf is a directed colimit of flat quasi-coherent sheaves of finite projective dimension. In the second part of the paper, we discuss cotorsion periodicity in category-theoretic context, generalizing an argument of Bazzoni, Cortés-Izurdiaga, and Estrada. As the main application, we deduce the assertion that any cotorsion-periodic quasi-coherent sheaf on a quasi-compact semi-separated scheme is cotorsion.</p></div>","PeriodicalId":50825,"journal":{"name":"Algebras and Representation Theory","volume":"27 6","pages":"2267 - 2293"},"PeriodicalIF":0.5,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10468-024-10296-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142994513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Clebsch-Gordan Coefficients for Macdonald Polynomials","authors":"Aritra Bhattacharya, Arun Ram","doi":"10.1007/s10468-024-10303-8","DOIUrl":"10.1007/s10468-024-10303-8","url":null,"abstract":"<div><p>In this paper we use the double affine Hecke algebra to compute the Macdonald polynomial products <span>(E_ell P_m)</span> and <span>(P_ell P_m)</span> for type <span>(SL_2)</span> and type <span>(GL_2)</span> Macdonald polynomials. Our method follows the ideas of Martha Yip but executes a compression to reduce the sum from <span>(2cdot 3^{ell -1})</span> signed terms to <span>(2ell )</span> positive terms. We show that our rule for <span>(P_ell P_m)</span> is equivalent to a special case of the Pieri rule of Macdonald. Our method shows that computing <span>(E_ell {textbf {1}}_0)</span> and <span>({textbf {1}}_0 E_ell {textbf {1}}_0)</span> in terms of a special basis of the double affine Hecke algebra provides universal compressed formulas for multiplication by <span>(E_ell )</span> and <span>(P_ell )</span>. The formulas for a specific products <span>(E_ell P_m)</span> and <span>(P_ell P_m)</span> are obtained by evaluating the universal formulas at <span>(t^{-frac{1}{2}}q^{-frac{m}{2}})</span>.</p></div>","PeriodicalId":50825,"journal":{"name":"Algebras and Representation Theory","volume":"27 6","pages":"2423 - 2464"},"PeriodicalIF":0.5,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10468-024-10303-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142994514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Isomorphism Problems and Groups of Automorphisms for Ore Extensions (K[x][y; ffrac{d}{dx} ]) (Prime Characteristic)","authors":"V. V. Bavula","doi":"10.1007/s10468-024-10301-w","DOIUrl":"10.1007/s10468-024-10301-w","url":null,"abstract":"<div><p>Let <span>(Lambda (f) = K[x][y; ffrac{d}{dx} ])</span> be an Ore extension of a polynomial algebra <i>K</i>[<i>x</i>] over an arbitrary field <i>K</i> of characteristic <span>(p>0)</span> where <span>(fin K[x])</span>. For each polynomial <i>f</i>, the automorphism group of the algebras <span>(Lambda (f))</span> is explicitly described. The automorphism group <span>(textrm{Aut}_K(Lambda (f))=mathbb {S}rtimes G_f)</span> is a semidirect product of two explicit groups where <span>(G_f)</span> is the <i>eigengroup</i> of the polynomial <i>f</i> (the set of all automorphisms of <i>K</i>[<i>x</i>] such that <i>f</i> is their common eigenvector). For each polynomial <i>f</i>, the eigengroup <span>(G_f)</span> is explicitly described. It is proven that every subgroup of <span>(textrm{Aut}_K(K[x]))</span> is the eigengroup of a polynomial. It is proven that the Krull and global dimensions of the algebra <span>(Lambda (f))</span> are 2. The prime, completely prime, primitive and maximal ideals of the algebra <span>(Lambda (f))</span> are classified.</p></div>","PeriodicalId":50825,"journal":{"name":"Algebras and Representation Theory","volume":"27 6","pages":"2389 - 2422"},"PeriodicalIF":0.5,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10468-024-10301-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142994558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Hopf Algebra (Co)actions on Rational Functions","authors":"Ulrich Krähmer, Blessing Bisola Oni","doi":"10.1007/s10468-024-10294-6","DOIUrl":"10.1007/s10468-024-10294-6","url":null,"abstract":"<div><p>In the theory of quantum automorphism groups, one constructs Hopf algebras acting on an algebra <i>K</i> from certain algebra morphisms <span>( sigma :K rightarrow textrm{M}_n(K))</span>. This approach is applied to the field <span>(K=k(t))</span> of rational functions, and it is investigated when these actions restrict to actions on the coordinate ring <span>(B=k[t^2,t^3])</span> of the cusp. An explicit example is described in detail and shown to define a new quantum homogeneous space structure on the cusp.</p></div>","PeriodicalId":50825,"journal":{"name":"Algebras and Representation Theory","volume":"27 6","pages":"2187 - 2216"},"PeriodicalIF":0.5,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10468-024-10294-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"3-Preprojective Algebras of Type D","authors":"Jordan Haden","doi":"10.1007/s10468-024-10297-3","DOIUrl":"10.1007/s10468-024-10297-3","url":null,"abstract":"<div><p>We present a family of selfinjective algebras of type D, which arise from the 3-preprojective algebras of type A by taking a <span>(mathbb {Z}_3)</span>-quotient. We show that a subset of these are themselves 3-preprojective algebras, and that the associated 2-representation-finite algebras are fractional Calabi-Yau. In addition, we show our work is connected to modular invariants for SU(3).</p></div>","PeriodicalId":50825,"journal":{"name":"Algebras and Representation Theory","volume":"27 6","pages":"2295 - 2320"},"PeriodicalIF":0.5,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10468-024-10297-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}