scholarly journals Behaviour of Green Lines at Royden’s Boundary of Riemann Surfaces

1964 ◽  
Vol 24 ◽  
pp. 1-27 ◽  
Author(s):  
Mitsuru Nakai

The aim of this paper is to investigate the behaviour of Green lines at Royden’s boundary Γ of a Riemann surface R with the Green function g(z, o) with the fixed pole o in R. We denote by the totality of Green lines L issuing from the fixed point o.

1966 ◽  
Vol 18 ◽  
pp. 399-403 ◽  
Author(s):  
Michael Voichick

In this paper we generalize to Riemann surfaces a theorem of Helson and Lowdenslager in (2) describing the closed subspaces of L2(﹛|z| = 1﹜) that are invariant under multiplication by eiθ.Let R be a region on a Riemann surface with boundary Γ consisting of a finite number of disjoint simple closed analytic curves such that R ⋃ Γ is compact and R lies on one side of Γ. Let dμ be the harmonic measure on Γ with respect to a fixed point t0 on R. We shall consider the closed subspaces of L2(Γ, dμ) that are invariant under multiplication by functions in A (R) = ﹛F|F continuous on , analytic on R}.


1964 ◽  
Vol 24 ◽  
pp. 205-239 ◽  
Author(s):  
Mitsuru Nakai

Let R be a hyperbolic Riemann surface and gw(z) be the Green function on R with its pole w in R. We denote by (R) the totality of sequences of points in R not accumulating in R and


Author(s):  
Linlin Sun ◽  
Jingyong Zhu

AbstractWe consider an evolution problem associated to the Kazdan–Warner equation on a closed Riemann surface $$(\Sigma ,g)$$ ( Σ , g ) $$\begin{aligned} -\Delta _{g}u=8\pi \left( \dfrac{he^{u}}{\int _{\Sigma }he^{u}\mathop {}\mathrm {d}\mu _{g}}-\dfrac{1}{\int _{\Sigma }\mathop {}\mathrm {d}\mu _{g}}\right) \end{aligned}$$ - Δ g u = 8 π h e u ∫ Σ h e u d μ g - 1 ∫ Σ d μ g where the prescribed function $$h\ge 0$$ h ≥ 0 and $$\max _{\Sigma }h>0$$ max Σ h > 0 . We prove the global existence and convergence under additional assumptions such as $$\begin{aligned} \Delta _{g}\ln h(p_0)+8\pi -2K(p_0)>0 \end{aligned}$$ Δ g ln h ( p 0 ) + 8 π - 2 K ( p 0 ) > 0 for any maximum point $$p_0$$ p 0 of the sum of $$2\ln h$$ 2 ln h and the regular part of the Green function, where K is the Gaussian curvature of $$\Sigma $$ Σ . In particular, this gives a new proof of the existence result by Yang and Zhu (Pro Am Math Soc 145:3953–3959, 2017) which generalizes existence result of Ding et al. (Asian J Math 1:230–248, 1997) to the non-negative prescribed function case.


2011 ◽  
Vol 2011 ◽  
pp. 1-20 ◽  
Author(s):  
Moustafa El-Shahed ◽  
Wafa M. Shammakh

We investigate an m-point boundary value problem for nonlinear fractional differential equations. The associated Green function for the boundary value problem is given at first, and some useful properties of the Green function are obtained. By using the fixed point theorems of cone expansion and compression of norm type and Leggett-Williams fixed point theorem, the existence of multiple positive solutions is obtained.


2011 ◽  
Vol 2011 ◽  
pp. 1-19 ◽  
Author(s):  
A. Guezane-Lakoud ◽  
R. Khaldi

A fractional boundary value problem is considered. By means of Banach contraction principle, Leray-Schauder nonlinear alternative, properties of the Green function, and Guo-Krasnosel'skii fixed point theorem on cone, some results on the existence, uniqueness, and positivity of solutions are obtained.


2021 ◽  
Vol 19 (1) ◽  
pp. 990-1006
Author(s):  
Xueqin Cao ◽  
Chenghua Gao ◽  
Duihua Duan

Abstract In this paper, we discuss the existence of positive solutions to a discrete third-order three-point boundary value problem. Here, the weight function a ( t ) a\left(t) and the Green function G ( t , s ) G\left(t,s) both change their sign. Despite this, we also obtain several existence results of positive solutions by using the Guo-Krasnoselskii’s fixed-point theorem in a cone.


Symmetry ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 122 ◽  
Author(s):  
Xinan Hao ◽  
Luyao Zhang

We study the existence, multiplicity, and uniqueness results of positive solutions for a fractional thermostat model. Our approach depends on the fixed point index theory, iterative method, and nonsymmetry property of the Green function. The properties of positive solutions depending on a parameter are also discussed.


Author(s):  
Ewa Kozłowska-Walania

AbstractWe consider Riemann surfaces of even genus g with the action of the group $$\mathcal {D}_n\times \mathbb {Z}_2$$ D n × Z 2 , with n even. These surfaces have the maximal number of 4 non-conjugate symmetries and shall be called s-extremal. We show various results for such surfaces, concerning the total number of ovals, topological types of symmetries, hyperellipticity degree and the minimal genus problem. If in addition an s-extremal Riemann surface has the maximal total number of ovals, then it shall simply be called extremal. In the main result of the paper we find all the families of extremal Riemann surfaces of even genera, depending on if one of the symmetries is fixed-point free or not.


2012 ◽  
Vol 09 (08) ◽  
pp. 1250063
Author(s):  
K. M. BUGAJSKA

We show that for any fixed point P0 on a Riemann surface Σ the distinct realizations of cocycles in [Formula: see text] correspond to the natural appearances of the standard Heisenberg vertex operator algebra Π(P0) and to the commutative Heisenberg vertex operator algebra Π0(P0), respectively.


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