In this note we show that the integral means spectrum of any univalent function admitting a quasiconformal extension to the extended complex plane is strictly less than the universal integral means spectrum. This gives an affirmative answer to a question raised in our recent paper.
{"title":"On the integral means spectrum of univalent functions with quasconformal extensions","authors":"Jianjun Jin","doi":"arxiv-2407.19240","DOIUrl":"https://doi.org/arxiv-2407.19240","url":null,"abstract":"In this note we show that the integral means spectrum of any univalent\u0000function admitting a quasiconformal extension to the extended complex plane is\u0000strictly less than the universal integral means spectrum. This gives an\u0000affirmative answer to a question raised in our recent paper.","PeriodicalId":501142,"journal":{"name":"arXiv - MATH - Complex Variables","volume":"59 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141866085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
On a compact Riemann surface $X$ of genus $g$, one of the questions is the existence of meromorphic functions having poles at a point $P$ on $X$. One of the theorems is the Weierstrass gap theorem that determines a sequence of $g$ numbers $1 < n_k < 2g$, $1 leq k leq g$ for which a meromorphic function with the order with $n_k$ fails to exist at $P$. In this note, we give proof of the Weierstrass gap theorem in cohomology terminology. We see that an interesting combinatorial problem may be formed as a byproduct from the statement of the Weierstrass gap theorem.
在属$g$的紧凑黎曼曲面$X$上,其中一个问题是在$X$上的点$P$上存在有极点的分形函数。其中一个定理是魏尔斯特拉斯间隙定理(Weierstrass gap theorem),该定理确定了一个$g$数序列:$1 < n_k < 2g$,$1 leq k leq g$,对于该序列,在$P$处不存在阶数为$n_k$的分垂函数。在本注中,我们用同调术语证明了韦尔斯特拉斯缺口定理。我们发现,从韦尔斯特拉斯间隙定理的陈述中可以得到一个有趣的组合问题作为副产品。
{"title":"A note on meromorphic functions on a compact Riemann surface having poles at a single point","authors":"V V Hemasundar Gollakota","doi":"arxiv-2407.18286","DOIUrl":"https://doi.org/arxiv-2407.18286","url":null,"abstract":"On a compact Riemann surface $X$ of genus $g$, one of the questions is the\u0000existence of meromorphic functions having poles at a point $P$ on $X$. One of\u0000the theorems is the Weierstrass gap theorem that determines a sequence of $g$\u0000numbers $1 < n_k < 2g$, $1 leq k leq g$ for which a meromorphic function with\u0000the order with $n_k$ fails to exist at $P$. In this note, we give proof of the\u0000Weierstrass gap theorem in cohomology terminology. We see that an interesting\u0000combinatorial problem may be formed as a byproduct from the statement of the\u0000Weierstrass gap theorem.","PeriodicalId":501142,"journal":{"name":"arXiv - MATH - Complex Variables","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141866086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper is the final step in solving the problem of starlikeness of Teichmuller spaces in Bers' embedding. This step concerns the case of finite dimensional Teichmuller spaces ${mathbf T}(g, n)$ of positive dimension (corresponding to punctured Riemann surfaces of finite conformal type $(g, n)$ with $2g - 2 + n > 0$).
{"title":"All Teichmuller spaces are not starlike","authors":"Samuel L. Krushkal","doi":"arxiv-2407.18239","DOIUrl":"https://doi.org/arxiv-2407.18239","url":null,"abstract":"This paper is the final step in solving the problem of starlikeness of\u0000Teichmuller spaces in Bers' embedding. This step concerns the case of finite\u0000dimensional Teichmuller spaces ${mathbf T}(g, n)$ of positive dimension\u0000(corresponding to punctured Riemann surfaces of finite conformal type $(g, n)$\u0000with $2g - 2 + n > 0$).","PeriodicalId":501142,"journal":{"name":"arXiv - MATH - Complex Variables","volume":"67 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141772585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In 1939 P'al Tur'an and J'anos ErH{o}d initiated the study of lower estimations of maximum norms of derivatives of polynomials, in terms of the maximum norms of the polynomials themselves, on convex domains of the complex plane. As a matter of normalization they considered the family $mathcal{P}_n(K)$ of degree $n$ polynomials with all zeros lying in the given convex, compact subset $KSubset {mathbb C}$. While Tur'an obtained the first results for the interval $I:=[-1,1]$ and the disk $D:={ zin {mathbb C}~:~ |z|le 1}$, ErH{o}d extended investigations to other compact convex domains, too. The order of the optimal constant was found to be $sqrt{n}$ for $I$ and $n$ for $D$. It took until 2006 to clarify that all compact convex emph{domains} (with nonempty interior), follow the pattern of the disk, and admit an order $n$ inequality. For $L^q(partial K)$ norms with any $1le q