<p>The Gauss map of a conformal minimal immersion of an open Riemann surface <i>M</i> into <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\mathbb {R}^n\)</EquationSource> </InlineEquation>, <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(n\ge 3\)</EquationSource> </InlineEquation>, is a holomorphic map <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(M\rightarrow \textbf{Q}^{n-2}\subset \mathbb {C}\mathbb {P}^{n-1}\)</EquationSource> </InlineEquation>. Denote by <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(\textrm{CMI}_{\textrm{full}}(M,\mathbb {R}^n)\)</EquationSource> </InlineEquation> and <InlineEquation ID="IEq5"> <EquationSource Format="TEX">\(\mathscr {O}_{\textrm{full}}(M,\textbf{Q}^{n-2})\)</EquationSource> </InlineEquation> the spaces of full conformal minimal immersions <InlineEquation ID="IEq6"> <EquationSource Format="TEX">\(M\rightarrow \mathbb {R}^n\)</EquationSource> </InlineEquation> and full holomorphic maps <InlineEquation ID="IEq7"> <EquationSource Format="TEX">\(M\rightarrow \textbf{Q}^{n-2}\)</EquationSource> </InlineEquation>, respectively, endowed with the compact-open topology. In this paper we show that the Gauss map assignment <InlineEquation ID="IEq8"> <EquationSource Format="TEX">\(\mathscr {G}:\textrm{CMI}_{\textrm{full}}(M,\mathbb {R}^n)\rightarrow \mathscr {O}_{\textrm{full}}(M,\textbf{Q}^{n-2})\)</EquationSource> </InlineEquation>, taking a full conformal minimal immersion to its Gauss map, is an open map. This implies, in view of a result of Forstnerič and the authors, that <InlineEquation ID="IEq9"> <EquationSource Format="TEX">\(\mathscr {G}\)</EquationSource> </InlineEquation> is a quotient map. The same results hold for the map <InlineEquation ID="IEq10"> <EquationSource Format="TEX">\((\mathscr {G},\textrm{Flux}):\textrm{CMI}_{\textrm{full}}(M,\mathbb {R}^n)\rightarrow \mathscr {O}_{\textrm{full}}(M,\textbf{Q}^{n-2})\times H^1(M,\mathbb {R}^n)\)</EquationSource> </InlineEquation>, where <InlineEquation ID="IEq11"> <EquationSource Format="TEX">\(\textrm{Flux}:\textrm{CMI}_{\textrm{full}}(M,\mathbb {R}^n)\rightarrow H^1(M,\mathbb {R}^n)\)</EquationSource> </InlineEquation> is the flux assignment. As application, we establish that the set of maps <InlineEquation ID="IEq12"> <EquationSource Format="TEX">\(G\in \mathscr {O}_{\textrm{full}}(M,\textbf{Q}^{n-2})\)</EquationSource> </InlineEquation> such that the family <InlineEquation ID="IEq13"> <EquationSource Format="TEX">\(\mathscr {G}^{-1}(G)\)</EquationSource> </InlineEquation> of all minimal surfaces in <InlineEquation ID="IEq14"> <EquationSource Format="TEX">\(\mathbb {R}^n\)</EquationSource> </InlineEquation> with the Gauss map <i>G</i> satisfies the classical Osserman curvature estimate, is meagre in the space of holomorphic maps <InlineEquation ID="IEq15"> <EquationSource Format="TEX">\(M\rightarrow \textbf{Q}^{n-2}\)</EquationSource> </InlineEquation>.</p>

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On the Gauss map assignment for minimal surfaces and the Osserman curvature estimate

  • Antonio Alarcón,
  • Francisco J. López

摘要

The Gauss map of a conformal minimal immersion of an open Riemann surface M into \(\mathbb {R}^n\) , \(n\ge 3\) , is a holomorphic map \(M\rightarrow \textbf{Q}^{n-2}\subset \mathbb {C}\mathbb {P}^{n-1}\) . Denote by \(\textrm{CMI}_{\textrm{full}}(M,\mathbb {R}^n)\) and \(\mathscr {O}_{\textrm{full}}(M,\textbf{Q}^{n-2})\) the spaces of full conformal minimal immersions \(M\rightarrow \mathbb {R}^n\) and full holomorphic maps \(M\rightarrow \textbf{Q}^{n-2}\) , respectively, endowed with the compact-open topology. In this paper we show that the Gauss map assignment \(\mathscr {G}:\textrm{CMI}_{\textrm{full}}(M,\mathbb {R}^n)\rightarrow \mathscr {O}_{\textrm{full}}(M,\textbf{Q}^{n-2})\) , taking a full conformal minimal immersion to its Gauss map, is an open map. This implies, in view of a result of Forstnerič and the authors, that \(\mathscr {G}\) is a quotient map. The same results hold for the map \((\mathscr {G},\textrm{Flux}):\textrm{CMI}_{\textrm{full}}(M,\mathbb {R}^n)\rightarrow \mathscr {O}_{\textrm{full}}(M,\textbf{Q}^{n-2})\times H^1(M,\mathbb {R}^n)\) , where \(\textrm{Flux}:\textrm{CMI}_{\textrm{full}}(M,\mathbb {R}^n)\rightarrow H^1(M,\mathbb {R}^n)\) is the flux assignment. As application, we establish that the set of maps \(G\in \mathscr {O}_{\textrm{full}}(M,\textbf{Q}^{n-2})\) such that the family \(\mathscr {G}^{-1}(G)\) of all minimal surfaces in \(\mathbb {R}^n\) with the Gauss map G satisfies the classical Osserman curvature estimate, is meagre in the space of holomorphic maps \(M\rightarrow \textbf{Q}^{n-2}\) .