Pub Date : 2024-05-14DOI: 10.1017/s0004972724000364
CHUNHONG LI, YUTIAN LEI
We use potential analysis to study the properties of positive solutions of a discrete Wolff-type equation $$ begin{align*} w(i)=W_{beta,gamma}(w^q)(i), quad i in mathbb{Z}^n. end{align*} $$
Here, $n geq 1$, $min {q,beta }>0$, $1<gamma leq 2$ and $beta gamma <n$. Such an equation can be used to study nonlinear problems on graphs appearing in the study of crystal lattices, neural networks and other discrete models. We use the method of regularity lifting to obtain an optimal summability of positive solutions of the equation. From this result, we obtain the decay rate of $w(i)$ when $|i| to infty $.
我们使用势分析来研究离散的沃尔夫型方程 $$ 的正解的性质: w(i)=W_{beta,gamma}(w^q)(i), quad i in mathbb{Z}^n.end{align*}$$Here, $n geq 1$, $min {q,beta }>0$, $1<gamma leq 2$ and $beta gamma <n$.这样的方程可以用来研究晶格、神经网络和其他离散模型研究中出现的图形上的非线性问题。我们利用正则性提升的方法获得了方程正解的最优求和性。根据这一结果,我们得到了当 $|i| to infty $ 时 $w(i)$ 的衰减率。
{"title":"SUMMABILITY AND ASYMPTOTICS OF POSITIVE SOLUTIONS OF AN EQUATION OF WOLFF TYPE","authors":"CHUNHONG LI, YUTIAN LEI","doi":"10.1017/s0004972724000364","DOIUrl":"https://doi.org/10.1017/s0004972724000364","url":null,"abstract":"<p>We use potential analysis to study the properties of positive solutions of a discrete Wolff-type equation <span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240514060414573-0998:S0004972724000364:S0004972724000364_eqnu1.png\"><span data-mathjax-type=\"texmath\"><span>$$ begin{align*} w(i)=W_{beta,gamma}(w^q)(i), quad i in mathbb{Z}^n. end{align*} $$</span></span></img></span></p><p>Here, <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240514060414573-0998:S0004972724000364:S0004972724000364_inline1.png\"><span data-mathjax-type=\"texmath\"><span>$n geq 1$</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:20240514060414573-0998:S0004972724000364:S0004972724000364_inline2.png\"><span data-mathjax-type=\"texmath\"><span>$min {q,beta }>0$</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:20240514060414573-0998:S0004972724000364:S0004972724000364_inline3.png\"><span data-mathjax-type=\"texmath\"><span>$1<gamma leq 2$</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:20240514060414573-0998:S0004972724000364:S0004972724000364_inline4.png\"><span data-mathjax-type=\"texmath\"><span>$beta gamma <n$</span></span></img></span></span>. Such an equation can be used to study nonlinear problems on graphs appearing in the study of crystal lattices, neural networks and other discrete models. We use the method of regularity lifting to obtain an optimal summability of positive solutions of the equation. From this result, we obtain the decay rate of <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240514060414573-0998:S0004972724000364:S0004972724000364_inline5.png\"><span data-mathjax-type=\"texmath\"><span>$w(i)$</span></span></img></span></span> when <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240514060414573-0998:S0004972724000364:S0004972724000364_inline6.png\"><span data-mathjax-type=\"texmath\"><span>$|i| to infty $</span></span></img></span></span>.</p>","PeriodicalId":50720,"journal":{"name":"Bulletin of the Australian Mathematical Society","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140942073","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 : 2024-05-13DOI: 10.1017/s0004972724000376
COLIN PETITJEAN
We prove that the set of elementary tensors is weakly closed in the projective tensor product of two Banach spaces. As a result, we answer a question of Rodríguez and Rueda Zoca [‘Weak precompactness in projective tensor products’, Indag. Math. (N.S.)35(1) (2024), 60–75], proving that if $(x_n) subset X$ and $(y_n) subset Y$ are two weakly null sequences such that $(x_n otimes y_n)$ converges weakly in $X widehat {otimes }_pi Y$ , then $(x_n otimes y_n)$ is also weakly null.
{"title":"THE SET OF ELEMENTARY TENSORS IS WEAKLY CLOSED IN PROJECTIVE TENSOR PRODUCTS","authors":"COLIN PETITJEAN","doi":"10.1017/s0004972724000376","DOIUrl":"https://doi.org/10.1017/s0004972724000376","url":null,"abstract":"We prove that the set of elementary tensors is weakly closed in the projective tensor product of two Banach spaces. As a result, we answer a question of Rodríguez and Rueda Zoca [‘Weak precompactness in projective tensor products’, <jats:italic>Indag. Math. (N.S.)</jats:italic>35(1) (2024), 60–75], proving that if <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0004972724000376_inline1.png\"/> <jats:tex-math> $(x_n) subset X$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> and <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0004972724000376_inline2.png\"/> <jats:tex-math> $(y_n) subset Y$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> are two weakly null sequences such that <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0004972724000376_inline3.png\"/> <jats:tex-math> $(x_n otimes y_n)$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> converges weakly in <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0004972724000376_inline4.png\"/> <jats:tex-math> $X widehat {otimes }_pi Y$ </jats:tex-math> </jats:alternatives> </jats:inline-formula>, then <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0004972724000376_inline5.png\"/> <jats:tex-math> $(x_n otimes y_n)$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> is also weakly null.","PeriodicalId":50720,"journal":{"name":"Bulletin of the Australian Mathematical Society","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140931572","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 : 2024-05-09DOI: 10.1017/s0004972724000248
XUJIAN HUANG, JIABIN LIU, SHUMING WANG
We prove that every smooth complex normed space X has the Wigner property. That is, for any complex normed space Y and every surjective mapping $f: Xrightarrow Y$ satisfying $$ begin{align*} {|f(x)+alpha f(y)|: alphain mathbb{T}}={|x+alpha y|: alphain mathbb{T}}, quad x,yin X, end{align*} $$ where $mathbb {T}$ is the unit circle of the complex plane, there exists a function $sigma : Xrightarrow mathbb {T}$ such that $sigma cdot f$ is a linear or anti-linear isometry. This is a variant of Wigner’s theorem for complex normed spaces.
{"title":"THE WIGNER PROPERTY OF SMOOTH NORMED SPACES","authors":"XUJIAN HUANG, JIABIN LIU, SHUMING WANG","doi":"10.1017/s0004972724000248","DOIUrl":"https://doi.org/10.1017/s0004972724000248","url":null,"abstract":"We prove that every smooth complex normed space <jats:italic>X</jats:italic> has the Wigner property. That is, for any complex normed space <jats:italic>Y</jats:italic> and every surjective mapping <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0004972724000248_inline1.png\"/> <jats:tex-math> $f: Xrightarrow Y$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> satisfying <jats:disp-formula> <jats:alternatives> <jats:graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0004972724000248_eqnu1.png\"/> <jats:tex-math> $$ begin{align*} {|f(x)+alpha f(y)|: alphain mathbb{T}}={|x+alpha y|: alphain mathbb{T}}, quad x,yin X, end{align*} $$ </jats:tex-math> </jats:alternatives> </jats:disp-formula> where <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0004972724000248_inline2.png\"/> <jats:tex-math> $mathbb {T}$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> is the unit circle of the complex plane, there exists a function <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0004972724000248_inline3.png\"/> <jats:tex-math> $sigma : Xrightarrow mathbb {T}$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> such that <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0004972724000248_inline4.png\"/> <jats:tex-math> $sigma cdot f$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> is a linear or anti-linear isometry. This is a variant of Wigner’s theorem for complex normed spaces.","PeriodicalId":50720,"journal":{"name":"Bulletin of the Australian Mathematical Society","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140941701","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 : 2024-05-06DOI: 10.1017/s0004972724000339
YOSHINORI HAMAHATA
In function fields in positive characteristic, we provide a concrete example of completely normal elements for a finite Galois extension. More precisely, for a nonabelian extension, we construct completely normal elements for Drinfeld modular function fields using Siegel functions in function fields. For an abelian extension, we construct completely normal elements for cyclotomic function fields.
{"title":"NORMAL BASES FOR FUNCTION FIELDS","authors":"YOSHINORI HAMAHATA","doi":"10.1017/s0004972724000339","DOIUrl":"https://doi.org/10.1017/s0004972724000339","url":null,"abstract":"<p>In function fields in positive characteristic, we provide a concrete example of completely normal elements for a finite Galois extension. More precisely, for a nonabelian extension, we construct completely normal elements for Drinfeld modular function fields using Siegel functions in function fields. For an abelian extension, we construct completely normal elements for cyclotomic function fields.</p>","PeriodicalId":50720,"journal":{"name":"Bulletin of the Australian Mathematical Society","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140885642","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 : 2024-05-06DOI: 10.1017/s0004972724000327
PENG GAO, LIANGYI ZHAO
We establish upper bounds for moments of smoothed quadratic Dirichlet character sums under the generalized Riemann hypothesis, confirming a conjecture of M. Jutila [‘On sums of real characters’, Tr. Mat. Inst. Steklova132 (1973), 247–250].
我们建立了广义黎曼假设下平滑二次狄利克特特征和的矩上限,证实了 M. 尤蒂拉的猜想['论实数特征和',Tr. Mat. Inst. Steklova 132 (1973), 247-250]。
{"title":"BOUNDS FOR MOMENTS OF QUADRATIC DIRICHLET CHARACTER SUMS","authors":"PENG GAO, LIANGYI ZHAO","doi":"10.1017/s0004972724000327","DOIUrl":"https://doi.org/10.1017/s0004972724000327","url":null,"abstract":"<p>We establish upper bounds for moments of smoothed quadratic Dirichlet character sums under the generalized Riemann hypothesis, confirming a conjecture of M. Jutila [‘On sums of real characters’, <span>Tr. Mat. Inst. Steklova</span> <span>132</span> (1973), 247–250].</p>","PeriodicalId":50720,"journal":{"name":"Bulletin of the Australian Mathematical Society","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140885300","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 : 2024-04-25DOI: 10.1017/s0004972724000285
D. A. Wolfram
We solve the problem of finding the inverse connection formulae for the generalised Bessel polynomials and their reciprocals, the reverse generalised Bessel polynomials. The connection formulae express monomials in terms of the generalised Bessel polynomials. They enable formulae for the elements of change of basis matrices for both kinds of generalised Bessel polynomials to be derived and proved correct directly.
{"title":"INVERSE CONNECTION FORMULAE FOR GENERALISED BESSEL POLYNOMIALS","authors":"D. A. Wolfram","doi":"10.1017/s0004972724000285","DOIUrl":"https://doi.org/10.1017/s0004972724000285","url":null,"abstract":"\u0000 We solve the problem of finding the inverse connection formulae for the generalised Bessel polynomials and their reciprocals, the reverse generalised Bessel polynomials. The connection formulae express monomials in terms of the generalised Bessel polynomials. They enable formulae for the elements of change of basis matrices for both kinds of generalised Bessel polynomials to be derived and proved correct directly.","PeriodicalId":50720,"journal":{"name":"Bulletin of the Australian Mathematical Society","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140655585","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}