{"title":"A parametrization of sheets of conjugacy classes in bad characteristic","authors":"F. Ambrosio, G. Carnovale, F. Esposito","doi":"10.4153/S0008439523000097","DOIUrl":"https://doi.org/10.4153/S0008439523000097","url":null,"abstract":"Abstract Let G be a simple algebraic group of adjoint type over an algebraically closed field k of bad characteristic. We show that its sheets of conjugacy classes are parametrized by G-conjugacy classes of pairs \u0000$(M,{mathcal O})$\u0000 where M is the identity component of the centralizer of a semisimple element in G and \u0000${mathcal O}$\u0000 is a rigid unipotent conjugacy class in M, in analogy with the good characteristic case.","PeriodicalId":55280,"journal":{"name":"Canadian Mathematical Bulletin-Bulletin Canadien De Mathematiques","volume":"66 1","pages":"976 - 983"},"PeriodicalIF":0.6,"publicationDate":"2022-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46194631","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":"Level compatibility in Sharifi’s conjecture","authors":"E. Lecouturier, Jun Wang","doi":"10.4153/s0008439523000267","DOIUrl":"https://doi.org/10.4153/s0008439523000267","url":null,"abstract":"Sharifi has constructed a map from the first homology of the modular curve $X_1(M)$ to the $K$-group $K_2(mathbf{Z}[zeta_M, frac{1}{M}])$, where $zeta_M$ is a primitive $M$th root of unity. We study how these maps relate when $M$ varies. Our method relies on the techniques developed by Sharifi and Venkatesh.","PeriodicalId":55280,"journal":{"name":"Canadian Mathematical Bulletin-Bulletin Canadien De Mathematiques","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48184100","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":"Determining sets for holomorphic functions on the symmetrized bidisk","authors":"Bata Krishna Das, Poornendu Kumar, H. Sau","doi":"10.4153/S0008439523000103","DOIUrl":"https://doi.org/10.4153/S0008439523000103","url":null,"abstract":"Abstract A subset \u0000${mathcal D}$\u0000 of a domain \u0000$Omega subset {mathbb C}^d$\u0000 is determining for an analytic function \u0000$f:Omega to overline {{mathbb D}}$\u0000 if whenever an analytic function \u0000$g:Omega rightarrow overline {{mathbb D}}$\u0000 coincides with f on \u0000${mathcal D}$\u0000 , equals to f on whole \u0000$Omega $\u0000 . This note finds several sufficient conditions for a subset of the symmetrized bidisk to be determining. For any \u0000$Ngeq 1$\u0000 , a set consisting of \u0000$N^2-N+1$\u0000 many points is constructed which is determining for any rational inner function with a degree constraint. We also investigate when the intersection of the symmetrized bidisk intersected with some special algebraic varieties can be determining for rational inner functions.","PeriodicalId":55280,"journal":{"name":"Canadian Mathematical Bulletin-Bulletin Canadien De Mathematiques","volume":"66 1","pages":"984 - 996"},"PeriodicalIF":0.6,"publicationDate":"2022-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48628260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The complexity of higher Chow groups","authors":"Genival da Silva, James D. Lewis","doi":"10.4153/S0008439522000509","DOIUrl":"https://doi.org/10.4153/S0008439522000509","url":null,"abstract":"Abstract Let \u0000$X/{mathbb C}$\u0000 be a smooth projective variety. We consider two integral invariants, one of which is the level of the Hodge cohomology algebra \u0000$H^*(X,{mathbb C})$\u0000 and the other involving the complexity of the higher Chow groups \u0000${mathrm {CH}}^*(X,m;{mathbb Q})$\u0000 for \u0000$mgeq 0$\u0000 . We conjecture that these two invariants are the same and accordingly provide some strong evidence in support of this.","PeriodicalId":55280,"journal":{"name":"Canadian Mathematical Bulletin-Bulletin Canadien De Mathematiques","volume":"66 1","pages":"903 - 911"},"PeriodicalIF":0.6,"publicationDate":"2022-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48046316","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":"From the Ideal Theorem to the class number","authors":"O. Bordellès","doi":"10.4153/s0008439523000425","DOIUrl":"https://doi.org/10.4153/s0008439523000425","url":null,"abstract":"In this note, we provide an explicit upper bound for $h_K mathcal{R}_K d_K^{-1/2}$ which depends on an effective constant in the error term of the Ideal Theorem.","PeriodicalId":55280,"journal":{"name":"Canadian Mathematical Bulletin-Bulletin Canadien De Mathematiques","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44082621","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":"Zero and uniqueness sets for Fock spaces","authors":"D. Aadi, Y. Omari","doi":"10.4153/S0008439522000492","DOIUrl":"https://doi.org/10.4153/S0008439522000492","url":null,"abstract":"Abstract We characterize zero sets for which every subset remains a zero set too in the Fock space \u0000$mathcal {F}^p$\u0000 , \u0000$1leq p<infty $\u0000 . We are also interested in the study of a stability problem for some examples of uniqueness set with zero excess in Fock spaces.","PeriodicalId":55280,"journal":{"name":"Canadian Mathematical Bulletin-Bulletin Canadien De Mathematiques","volume":"66 1","pages":"532 - 543"},"PeriodicalIF":0.6,"publicationDate":"2022-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49358167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On Hardy kernels as reproducing kernels","authors":"J. Oliva-Maza","doi":"10.4153/S0008439522000406","DOIUrl":"https://doi.org/10.4153/S0008439522000406","url":null,"abstract":"Abstract Hardy kernels are a useful tool to define integral operators on Hilbertian spaces like \u0000$L^2(mathbb R^+)$\u0000 or \u0000$H^2(mathbb C^+)$\u0000 . These kernels entail an algebraic \u0000$L^1$\u0000 -structure which is used in this work to study the range spaces of those operators as reproducing kernel Hilbert spaces. We obtain their reproducing kernels, which in the \u0000$L^2(mathbb R^+)$\u0000 case turn out to be Hardy kernels as well. In the \u0000$H^2(mathbb C^+)$\u0000 scenario, the reproducing kernels are given by holomorphic extensions of Hardy kernels. Other results presented here are theorems of Paley–Wiener type, and a connection with one-sided Hilbert transforms.","PeriodicalId":55280,"journal":{"name":"Canadian Mathematical Bulletin-Bulletin Canadien De Mathematiques","volume":"66 1","pages":"428 - 442"},"PeriodicalIF":0.6,"publicationDate":"2022-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45337449","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":"Groups whose Chermak–Delgado lattice is a subgroup lattice of an abelian group","authors":"Lijian An","doi":"10.4153/S0008439522000418","DOIUrl":"https://doi.org/10.4153/S0008439522000418","url":null,"abstract":"Abstract The Chermak–Delgado lattice of a finite group G is a self-dual sublattice of the subgroup lattice of G. In this paper, we prove that, for any finite abelian group A, there exists a finite group G such that the Chermak–Delgado lattice of G is a subgroup lattice of A.","PeriodicalId":55280,"journal":{"name":"Canadian Mathematical Bulletin-Bulletin Canadien De Mathematiques","volume":"66 1","pages":"443 - 449"},"PeriodicalIF":0.6,"publicationDate":"2022-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49098697","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":"Optimization of the anisotropic Cheeger constant with respect to the anisotropy","authors":"E. Parini, Giorgio Saracco","doi":"10.4153/S0008439523000152","DOIUrl":"https://doi.org/10.4153/S0008439523000152","url":null,"abstract":"Abstract Given an open, bounded set \u0000$Omega $\u0000 in \u0000$mathbb {R}^N$\u0000 , we consider the minimization of the anisotropic Cheeger constant \u0000$h_K(Omega )$\u0000 with respect to the anisotropy K, under a volume constraint on the associated unit ball. In the planar case, under the assumption that K is a convex, centrally symmetric body, we prove the existence of a minimizer. Moreover, if \u0000$Omega $\u0000 is a ball, we show that the optimal anisotropy K is not a ball and that, among all regular polygons, the square provides the minimal value.","PeriodicalId":55280,"journal":{"name":"Canadian Mathematical Bulletin-Bulletin Canadien De Mathematiques","volume":"66 1","pages":"1030 - 1043"},"PeriodicalIF":0.6,"publicationDate":"2022-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46083684","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 result on the c2 invariant for powers of primes","authors":"Maria S. Esipova, K. Yeats","doi":"10.4153/s0008439523000243","DOIUrl":"https://doi.org/10.4153/s0008439523000243","url":null,"abstract":"The $c_2$ invariant is an arithmetic graph invariant related to quantum field theory. We give a relation modulo $p$ between the $c_2$ invariant at $p$ and the $c_2$ invariant at $p^s$ by proving a relation modulo $p$ between certain coefficients of powers of products of particularly nice polynomials. The relation at the level of the $c_2$ invariant provides evidence for a conjecture of Schnetz.","PeriodicalId":55280,"journal":{"name":"Canadian Mathematical Bulletin-Bulletin Canadien De Mathematiques","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47433116","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}