Pub Date : 2024-03-06DOI: 10.1017/s1446788723000381
LANCELOT SEMAL
We classify the irreducible unitary representations of closed simple groups of automorphisms of trees acting $2$-transitively on the boundary and whose local action at every vertex contains the alternating group. As an application, we confirm Claudio Nebbia’s CCR conjecture on trees for $(d_0,d_1)$-semi-regular trees such that $d_0,d_1in Theta $, where $Theta $ is an asymptotically dense set of positive integers.
{"title":"RADU GROUPS ACTING ON TREES ARE CCR","authors":"LANCELOT SEMAL","doi":"10.1017/s1446788723000381","DOIUrl":"https://doi.org/10.1017/s1446788723000381","url":null,"abstract":"<p>We classify the irreducible unitary representations of closed simple groups of automorphisms of trees acting <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240305152040603-0270:S1446788723000381:S1446788723000381_inline1.png\"><span data-mathjax-type=\"texmath\"><span>$2$</span></span></img></span></span>-transitively on the boundary and whose local action at every vertex contains the alternating group. As an application, we confirm Claudio Nebbia’s CCR conjecture on trees for <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240305152040603-0270:S1446788723000381:S1446788723000381_inline2.png\"><span data-mathjax-type=\"texmath\"><span>$(d_0,d_1)$</span></span></img></span></span>-semi-regular trees such that <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240305152040603-0270:S1446788723000381:S1446788723000381_inline3.png\"><span data-mathjax-type=\"texmath\"><span>$d_0,d_1in Theta $</span></span></img></span></span>, where <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240305152040603-0270:S1446788723000381:S1446788723000381_inline4.png\"><span data-mathjax-type=\"texmath\"><span>$Theta $</span></span></img></span></span> is an asymptotically dense set of positive integers.</p>","PeriodicalId":50007,"journal":{"name":"Journal of the Australian Mathematical Society","volume":"27 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140047484","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}
Pub Date : 2024-02-28DOI: 10.1017/s1446788724000016
MARCO ANTONIO PELLEGRINI, MARIA CHIARA TAMBURINI BELLANI
The complete classification of the finite simple groups that are $(2,3)$ -generated is a problem which is still open only for orthogonal groups. Here, we construct $(2, 3)$ -generators for the finite odd-dimensional orthogonal groups $Omega _{2k+1}(q)$ , $kgeq 4$ . As a byproduct, we also obtain $(2,3)$ -generators for $Omega _{4k}^+(q)$ with $kgeq 3$ and q odd, and for $Omega _{4k+2}^pm (q)$ with $kgeq 4$ and $qequiv pm 1~ mathrm {(mod~ 4)}$ .
Pub Date : 2024-02-15DOI: 10.1017/s1446788723000393
JIE DING, JIANHUA ZHENG
This paper consists of two parts. The first is to study the existence of a point a at the intersection of the Julia set and the escaping set such that a goes to infinity under iterates along Julia directions or Borel directions. Additionally, we find such points that approximate all Borel directions to escape if the meromorphic functions have positive lower order. We confirm the existence of such slowly escaping points under a weaker growth condition. The second is to study the connection between the Fatou set and argument distribution. In view of the filling disks, we show nonexistence of multiply connected Fatou components if an entire function satisfies a weaker growth condition. We prove that the absence of singular directions implies the nonexistence of large annuli in the Fatou set.
本文由两部分组成。第一部分是研究在 Julia 集和逸散集的交点上是否存在一个点 a,使得 a 在沿着 Julia 方向或 Borel 方向迭代的情况下达到无穷大。此外,我们还发现了这样的点,即如果分形函数具有正低阶,则近似于所有 Borel 方向的逸出。我们在一个较弱的增长条件下证实了这种缓慢逸出点的存在。其次是研究法图集与参数分布之间的联系。鉴于填充盘的存在,我们证明了如果整个函数满足较弱的增长条件,多重连接的法图集分量是不存在的。我们证明了奇异方向的不存在意味着法图集合中大环面的不存在。
{"title":"ON THE ITERATIONS AND THE ARGUMENT DISTRIBUTION OF MEROMORPHIC FUNCTIONS","authors":"JIE DING, JIANHUA ZHENG","doi":"10.1017/s1446788723000393","DOIUrl":"https://doi.org/10.1017/s1446788723000393","url":null,"abstract":"This paper consists of two parts. The first is to study the existence of a point <jats:italic>a</jats:italic> at the intersection of the Julia set and the escaping set such that <jats:italic>a</jats:italic> goes to infinity under iterates along Julia directions or Borel directions. Additionally, we find such points that approximate all Borel directions to escape if the meromorphic functions have positive lower order. We confirm the existence of such slowly escaping points under a weaker growth condition. The second is to study the connection between the Fatou set and argument distribution. In view of the filling disks, we show nonexistence of multiply connected Fatou components if an entire function satisfies a weaker growth condition. We prove that the absence of singular directions implies the nonexistence of large annuli in the Fatou set.","PeriodicalId":50007,"journal":{"name":"Journal of the Australian Mathematical Society","volume":"53 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2024-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139768268","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}
Pub Date : 2024-01-17DOI: 10.1017/s144678872300037x
S. KALISZEWSKI, JOHN QUIGG, DANA P. WILLIAMS
We establish a generalized Rieffel correspondence for ideals in equivalent Fell bundles.
我们建立了等价费尔束中理想的广义里费尔对应关系。
{"title":"THE RIEFFEL CORRESPONDENCE FOR EQUIVALENT FELL BUNDLES","authors":"S. KALISZEWSKI, JOHN QUIGG, DANA P. WILLIAMS","doi":"10.1017/s144678872300037x","DOIUrl":"https://doi.org/10.1017/s144678872300037x","url":null,"abstract":"<p>We establish a generalized Rieffel correspondence for ideals in equivalent Fell bundles.</p>","PeriodicalId":50007,"journal":{"name":"Journal of the Australian Mathematical Society","volume":"19 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139482754","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}
Pub Date : 2024-01-15DOI: 10.1017/s1446788723000368
PENG CHEN, XIXI LIN
<p>Let <span>H</span> be the Hermite operator <span><span><img data-mimesubtype="png" data-type="" src="https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240114040524355-0595:S1446788723000368:S1446788723000368_inline2.png"><span data-mathjax-type="texmath"><span>$-Delta +|x|^2$</span></span></img></span></span> on <span><span><img data-mimesubtype="png" data-type="" src="https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240114040524355-0595:S1446788723000368:S1446788723000368_inline3.png"><span data-mathjax-type="texmath"><span>$mathbb {R}^n$</span></span></img></span></span>. We prove a weighted <span><span><img data-mimesubtype="png" data-type="" src="https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240114040524355-0595:S1446788723000368:S1446788723000368_inline4.png"><span data-mathjax-type="texmath"><span>$L^2$</span></span></img></span></span> estimate of the maximal commutator operator <span><span><img data-mimesubtype="png" data-type="" src="https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240114040524355-0595:S1446788723000368:S1446788723000368_inline5.png"><span data-mathjax-type="texmath"><span>$sup _{R>0}|[b, S_R^lambda (H)](f)|$</span></span></img></span></span>, where <span><span><img data-mimesubtype="png" data-type="" src="https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240114040524355-0595:S1446788723000368:S1446788723000368_inline6.png"><span data-mathjax-type="texmath"><span>$ [b, S_R^lambda (H)](f) = bS_R^lambda (H) f - S_R^lambda (H)(bf) $</span></span></img></span></span> is the commutator of a BMO function <span>b</span> and the Bochner–Riesz means <span><span><img data-mimesubtype="png" data-type="" src="https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240114040524355-0595:S1446788723000368:S1446788723000368_inline7.png"><span data-mathjax-type="texmath"><span>$S_R^lambda (H)$</span></span></img></span></span> for the Hermite operator <span>H</span>. As an application, we obtain the almost everywhere convergence of <span><span><img data-mimesubtype="png" data-type="" src="https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240114040524355-0595:S1446788723000368:S1446788723000368_inline8.png"><span data-mathjax-type="texmath"><span>$[b, S_R^lambda (H)](f)$</span></span></img></span></span> for large <span><span><img data-mimesubtype="png" data-type="" src="https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240114040524355-0595:S1446788723000368:S1446788723000368_inline9.png"><span data-mathjax-type="texmath"><span>$lambda $</span></span></img></span></span> and <span><span><img data-mimesubtype="png" data-type="" src="https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240114040524355-0595:S1446788723000368:S1446788723000368_inline10.png"><span data-mathjax-type="texmath"><span>$fin
假设 H 是 $mathbb {R}^n$ 上的赫米特算子 $-Delta +|x|^2$ 。我们将证明最大换元算子 $sup _{R>;0}|[b,S_R^/lambda (H)](f)|$ 其中 $ [b, S_R^lambda (H)](f) = bS_R^lambda (H) f - S_R^lambda (H)(bf) $ 是 BMO 函数 b 的换元子和 Hermite 算子 H 的 Bochner-Riesz means $S_R^/lambda(H)$。作为应用,我们得到了 $[b, S_R^lambda (H)](f)$ 对于大 $lambda $ 和 $fin L^p(mathbb {R}^n)$ 的几乎无处收敛性。
{"title":"A WEIGHTED ESTIMATE OF COMMUTATORS OF BOCHNER–RIESZ OPERATORS FOR HERMITE OPERATOR","authors":"PENG CHEN, XIXI LIN","doi":"10.1017/s1446788723000368","DOIUrl":"https://doi.org/10.1017/s1446788723000368","url":null,"abstract":"<p>Let <span>H</span> be the Hermite operator <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240114040524355-0595:S1446788723000368:S1446788723000368_inline2.png\"><span data-mathjax-type=\"texmath\"><span>$-Delta +|x|^2$</span></span></img></span></span> on <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240114040524355-0595:S1446788723000368:S1446788723000368_inline3.png\"><span data-mathjax-type=\"texmath\"><span>$mathbb {R}^n$</span></span></img></span></span>. We prove a weighted <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240114040524355-0595:S1446788723000368:S1446788723000368_inline4.png\"><span data-mathjax-type=\"texmath\"><span>$L^2$</span></span></img></span></span> estimate of the maximal commutator operator <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240114040524355-0595:S1446788723000368:S1446788723000368_inline5.png\"><span data-mathjax-type=\"texmath\"><span>$sup _{R>0}|[b, S_R^lambda (H)](f)|$</span></span></img></span></span>, where <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240114040524355-0595:S1446788723000368:S1446788723000368_inline6.png\"><span data-mathjax-type=\"texmath\"><span>$ [b, S_R^lambda (H)](f) = bS_R^lambda (H) f - S_R^lambda (H)(bf) $</span></span></img></span></span> is the commutator of a BMO function <span>b</span> and the Bochner–Riesz means <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240114040524355-0595:S1446788723000368:S1446788723000368_inline7.png\"><span data-mathjax-type=\"texmath\"><span>$S_R^lambda (H)$</span></span></img></span></span> for the Hermite operator <span>H</span>. As an application, we obtain the almost everywhere convergence of <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240114040524355-0595:S1446788723000368:S1446788723000368_inline8.png\"><span data-mathjax-type=\"texmath\"><span>$[b, S_R^lambda (H)](f)$</span></span></img></span></span> for large <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240114040524355-0595:S1446788723000368:S1446788723000368_inline9.png\"><span data-mathjax-type=\"texmath\"><span>$lambda $</span></span></img></span></span> and <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240114040524355-0595:S1446788723000368:S1446788723000368_inline10.png\"><span data-mathjax-type=\"texmath\"><span>$fin","PeriodicalId":50007,"journal":{"name":"Journal of the Australian Mathematical Society","volume":"9 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2024-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139468895","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}
Pub Date : 2023-12-22DOI: 10.1017/s1446788723000162
Claude Marion, P. V. Silva, Gareth Tracey
We prove that, given a finitely generated subgroup H of a free group F, the following questions are decidable: is H closed (dense) in F for the pro-(met)abelian topology? Is the closure of H in F for the pro-(met)abelian topology finitely generated? We show also that if the latter question has a positive answer, then we can effectively construct a basis for the closure, and the closure has decidable membership problem in any case. Moreover, it is decidable whether H is closed for the pro- $mathbf {V}$ topology when $mathbf {V}$ is an equational pseudovariety of finite groups, such as the pseudovariety $mathbf {S}_k$ of all finite solvable groups with derived length $leq k$ . We also connect the pro-abelian topology with the topologies defined by abelian groups of bounded exponent.
我们证明,给定自由群 F 的有限生成子群 H,下列问题是可解的:对于原(元)阿贝尔拓扑学,H 在 F 中封闭(致密)吗?在亲(元)阿贝尔拓扑中,H 在 F 中的闭是有限生成的吗?我们还将证明,如果后一个问题的答案是肯定的,那么我们就能有效地为闭包构造一个基础,而且闭包在任何情况下都有可解的成员问题。此外,当$mathbf {V}$是有限群的等价伪变体时,比如所有派生长度为$leq k$的有限可解群的伪变体$mathbf {S}_k$ ,对于亲$mathbf {V}$拓扑来说,H是否封闭也是可解的。我们还将原阿贝尔拓扑与有界幂的无性群定义的拓扑联系起来。
{"title":"THE PRO--SOLVABLE TOPOLOGY ON A FREE GROUP","authors":"Claude Marion, P. V. Silva, Gareth Tracey","doi":"10.1017/s1446788723000162","DOIUrl":"https://doi.org/10.1017/s1446788723000162","url":null,"abstract":"\u0000 We prove that, given a finitely generated subgroup H of a free group F, the following questions are decidable: is H closed (dense) in F for the pro-(met)abelian topology? Is the closure of H in F for the pro-(met)abelian topology finitely generated? We show also that if the latter question has a positive answer, then we can effectively construct a basis for the closure, and the closure has decidable membership problem in any case. Moreover, it is decidable whether H is closed for the pro-\u0000 \u0000 \u0000 \u0000$mathbf {V}$\u0000\u0000 \u0000 topology when \u0000 \u0000 \u0000 \u0000$mathbf {V}$\u0000\u0000 \u0000 is an equational pseudovariety of finite groups, such as the pseudovariety \u0000 \u0000 \u0000 \u0000$mathbf {S}_k$\u0000\u0000 \u0000 of all finite solvable groups with derived length \u0000 \u0000 \u0000 \u0000$leq k$\u0000\u0000 \u0000 . We also connect the pro-abelian topology with the topologies defined by abelian groups of bounded exponent.","PeriodicalId":50007,"journal":{"name":"Journal of the Australian Mathematical Society","volume":"42 32","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138946488","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}
Pub Date : 2023-12-18DOI: 10.1017/s1446788723000150
ARUP CHATTOPADHYAY, DEBKUMAR GIRI, R. K. SRIVASTAVA
In this article, we study the recent development of the qualitative uncertainty principle on certain Lie groups. In particular, we consider that if the Weyl transform on certain step-two nilpotent Lie groups is of finite rank, then the function has to be zero almost everywhere as long as the nonvanishing set for the function has finite measure. Further, we consider that if the Weyl transform of each Fourier–Wigner piece of a suitable function on the Heisenberg motion group is of finite rank, then the function has to be zero almost everywhere whenever the nonvanishing set for each Fourier–Wigner piece has finite measure.
{"title":"QUALITATIVE UNCERTAINTY PRINCIPLE ON CERTAIN LIE GROUPS","authors":"ARUP CHATTOPADHYAY, DEBKUMAR GIRI, R. K. SRIVASTAVA","doi":"10.1017/s1446788723000150","DOIUrl":"https://doi.org/10.1017/s1446788723000150","url":null,"abstract":"<p>In this article, we study the recent development of the qualitative uncertainty principle on certain Lie groups. In particular, we consider that if the Weyl transform on certain step-two nilpotent Lie groups is of finite rank, then the function has to be zero almost everywhere as long as the nonvanishing set for the function has finite measure. Further, we consider that if the Weyl transform of each Fourier–Wigner piece of a suitable function on the Heisenberg motion group is of finite rank, then the function has to be zero almost everywhere whenever the nonvanishing set for each Fourier–Wigner piece has finite measure.</p>","PeriodicalId":50007,"journal":{"name":"Journal of the Australian Mathematical Society","volume":"116 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138716298","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}
Pub Date : 2023-12-18DOI: 10.1017/s1446788723000204
JOSEP ELGUETA
<p>A notion of <span>normal submonoid</span> of a monoid <span>M</span> is introduced that generalizes the normal subgroups of a group. When ordered by inclusion, the set <span><span><img data-mimesubtype="png" data-type="" src="https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20231215153200057-0472:S1446788723000204:S1446788723000204_inline1.png"><span data-mathjax-type="texmath"><span>$mathsf {NorSub}(M)$</span></span></img></span></span> of normal submonoids of <span>M</span> is a complete lattice. Joins are explicitly described and the lattice is computed for the finite full transformation monoids <span><span><img data-mimesubtype="png" data-type="" src="https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20231215153200057-0472:S1446788723000204:S1446788723000204_inline2.png"><span data-mathjax-type="texmath"><span>$T_n$</span></span></img></span></span>, <span><span><img data-mimesubtype="png" data-type="" src="https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20231215153200057-0472:S1446788723000204:S1446788723000204_inline3.png"><span data-mathjax-type="texmath"><span>$ngeq ~1$</span></span></img></span></span>. It is also shown that <span><span><img data-mimesubtype="png" data-type="" src="https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20231215153200057-0472:S1446788723000204:S1446788723000204_inline4.png"><span data-mathjax-type="texmath"><span>$mathsf {NorSub}(M)$</span></span></img></span></span> is modular for a specific family of commutative monoids, including all Krull monoids, and that it, as a join semilattice, embeds isomorphically onto a join subsemilattice of the lattice <span><span><img data-mimesubtype="png" data-type="" src="https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20231215153200057-0472:S1446788723000204:S1446788723000204_inline5.png"><span data-mathjax-type="texmath"><span>$mathsf {Cong}(M)$</span></span></img></span></span> of congruences on <span>M</span>. This leads to a new strategy for computing <span><span><img data-mimesubtype="png" data-type="" src="https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20231215153200057-0472:S1446788723000204:S1446788723000204_inline6.png"><span data-mathjax-type="texmath"><span>$mathsf {Cong}(M)$</span></span></img></span></span> consisting of computing <span><span><img data-mimesubtype="png" data-type="" src="https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20231215153200057-0472:S1446788723000204:S1446788723000204_inline7.png"><span data-mathjax-type="texmath"><span>$mathsf {NorSub}(M)$</span></span></img></span></span> and the so-called unital congruences on the quotients of <span>M</span> modulo its normal submonoids. This provides a new perspective on Malcev’s computation of the congruences on <span><span><img data-mimesubtype="png" data-type="" src="https://static.cambridge.org/binary/version/id
本文引入了一个单元 M 的正则子单元的概念,它概括了一个群的正则子群。当通过包含排序时,M 的正则子单体集合 $mathsf {NorSub}(M)$ 是一个完整的网格。明确描述了连接,并计算了有限全变换单体 $T_n$,$ngeq ~1$的网格。研究还表明,$mathsf {NorSub}(M)$ 对于一个特定的交换单体族(包括所有的 Krull 单体)来说是模块化的,而且它作为一个连接半网格,同构地嵌入到 M 上全等的网格 $mathsf {Cong}(M)$ 的连接子半格上。这就引出了一种计算 $mathsf {Cong}(M)$ 的新策略,它包括计算 $mathsf {NorSub}(M)$ 和 M 的商上的所谓unital congruences modulo its normal submonoids。这为马尔切夫计算 $T_n$ 上的同余提供了一个新视角。
{"title":"NORMAL SUBMONOIDS AND CONGRUENCES ON A MONOID","authors":"JOSEP ELGUETA","doi":"10.1017/s1446788723000204","DOIUrl":"https://doi.org/10.1017/s1446788723000204","url":null,"abstract":"<p>A notion of <span>normal submonoid</span> of a monoid <span>M</span> is introduced that generalizes the normal subgroups of a group. When ordered by inclusion, the set <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20231215153200057-0472:S1446788723000204:S1446788723000204_inline1.png\"><span data-mathjax-type=\"texmath\"><span>$mathsf {NorSub}(M)$</span></span></img></span></span> of normal submonoids of <span>M</span> is a complete lattice. Joins are explicitly described and the lattice is computed for the finite full transformation monoids <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20231215153200057-0472:S1446788723000204:S1446788723000204_inline2.png\"><span data-mathjax-type=\"texmath\"><span>$T_n$</span></span></img></span></span>, <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20231215153200057-0472:S1446788723000204:S1446788723000204_inline3.png\"><span data-mathjax-type=\"texmath\"><span>$ngeq ~1$</span></span></img></span></span>. It is also shown that <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20231215153200057-0472:S1446788723000204:S1446788723000204_inline4.png\"><span data-mathjax-type=\"texmath\"><span>$mathsf {NorSub}(M)$</span></span></img></span></span> is modular for a specific family of commutative monoids, including all Krull monoids, and that it, as a join semilattice, embeds isomorphically onto a join subsemilattice of the lattice <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20231215153200057-0472:S1446788723000204:S1446788723000204_inline5.png\"><span data-mathjax-type=\"texmath\"><span>$mathsf {Cong}(M)$</span></span></img></span></span> of congruences on <span>M</span>. This leads to a new strategy for computing <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20231215153200057-0472:S1446788723000204:S1446788723000204_inline6.png\"><span data-mathjax-type=\"texmath\"><span>$mathsf {Cong}(M)$</span></span></img></span></span> consisting of computing <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20231215153200057-0472:S1446788723000204:S1446788723000204_inline7.png\"><span data-mathjax-type=\"texmath\"><span>$mathsf {NorSub}(M)$</span></span></img></span></span> and the so-called unital congruences on the quotients of <span>M</span> modulo its normal submonoids. This provides a new perspective on Malcev’s computation of the congruences on <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id","PeriodicalId":50007,"journal":{"name":"Journal of the Australian Mathematical Society","volume":"69 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138717306","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}
Pub Date : 2023-12-15DOI: 10.1017/s1446788723000174
ANIMA NAGAR, PRADEEP SINGH
Bratteli–Vershik models of compact, invertible zero-dimensional systems have been well studied. We take up such a study for polygonal billiards on the hyperbolic plane, thus considering these models beyond zero-dimensions. We describe the associated Bratteli models and show that these billiard dynamics can be described by Vershik maps.
{"title":"BRATTELI–VERSHIKISABILITY OF POLYGONAL BILLIARDS ON THE HYPERBOLIC PLANE","authors":"ANIMA NAGAR, PRADEEP SINGH","doi":"10.1017/s1446788723000174","DOIUrl":"https://doi.org/10.1017/s1446788723000174","url":null,"abstract":"Bratteli–Vershik models of compact, invertible zero-dimensional systems have been well studied. We take up such a study for polygonal billiards on the hyperbolic plane, thus considering these models beyond zero-dimensions. We describe the associated Bratteli models and show that these billiard dynamics can be described by Vershik maps.","PeriodicalId":50007,"journal":{"name":"Journal of the Australian Mathematical Society","volume":"12 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138681885","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}
Pub Date : 2023-12-13DOI: 10.1017/s1446788723000198
PEDRO V. SILVA, BENJAMIN STEINBERG
The complex algebra of an inverse semigroup with finitely many idempotents in each $mathcal D$-class is stably finite by a result of Munn. This can be proved fairly easily using $C^{*}$-algebras for inverse semigroups satisfying this condition that have a Hausdorff universal groupoid, or more generally for direct limits of inverse semigroups satisfying this condition and having Hausdorff universal groupoids. It is not difficult to see that a finitely presented inverse semigroup with a non-Hausdorff universal groupoid cannot be a direct limit of inverse semigroups with Hausdorff universal groupoids. We construct here countably many nonisomorphic finitely presented inverse semigroups with finitely many idempotents in each $mathcal D$-class and non-Hausdorff universal groupoids. At this time, there is not a clear $C^{*}$-algebraic technique to prove these inverse semigroups have stably finite complex algebras.
{"title":"FINITELY PRESENTED INVERSE SEMIGROUPS WITH FINITELY MANY IDEMPOTENTS IN EACH -CLASS AND NON-HAUSDORFF UNIVERSAL GROUPOIDS","authors":"PEDRO V. SILVA, BENJAMIN STEINBERG","doi":"10.1017/s1446788723000198","DOIUrl":"https://doi.org/10.1017/s1446788723000198","url":null,"abstract":"<p>The complex algebra of an inverse semigroup with finitely many idempotents in each <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20231212123316423-0307:S1446788723000198:S1446788723000198_inline2.png\"><span data-mathjax-type=\"texmath\"><span>$mathcal D$</span></span></img></span></span>-class is stably finite by a result of Munn. This can be proved fairly easily using <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20231212123316423-0307:S1446788723000198:S1446788723000198_inline3.png\"><span data-mathjax-type=\"texmath\"><span>$C^{*}$</span></span></img></span></span>-algebras for inverse semigroups satisfying this condition that have a Hausdorff universal groupoid, or more generally for direct limits of inverse semigroups satisfying this condition and having Hausdorff universal groupoids. It is not difficult to see that a finitely presented inverse semigroup with a non-Hausdorff universal groupoid cannot be a direct limit of inverse semigroups with Hausdorff universal groupoids. We construct here countably many nonisomorphic finitely presented inverse semigroups with finitely many idempotents in each <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20231212123316423-0307:S1446788723000198:S1446788723000198_inline4.png\"><span data-mathjax-type=\"texmath\"><span>$mathcal D$</span></span></img></span></span>-class and non-Hausdorff universal groupoids. At this time, there is not a clear <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20231212123316423-0307:S1446788723000198:S1446788723000198_inline5.png\"><span data-mathjax-type=\"texmath\"><span>$C^{*}$</span></span></img></span></span>-algebraic technique to prove these inverse semigroups have stably finite complex algebras.</p>","PeriodicalId":50007,"journal":{"name":"Journal of the Australian Mathematical Society","volume":"42 Pt B 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138578897","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}