<p>For a closed minimal submanifold <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="MediaObjects/12220_2026_2551_IEq1_HTML.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="120" Type="Linedraw" Width="95" /> </InlineMediaObject> </InlineEquation> in the unit sphere <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\((n&lt;N)\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mo stretchy="false">(</mo> <mi>n</mi> <mo>&lt;</mo> <mi>N</mi> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation>, we prove <Equation ID="Equ27"> <EquationSource Format="TEX">\(\begin{aligned} \textrm{Vol}(M^n) \ge \frac{n+1}{n+2} \int _{M}\left( 1+\varphi _{p}^2\right) \ge m\textrm{Vol}(\mathbb {S}^{n}), \end{aligned}\)</EquationSource> <EquationSource Format="MATHML"><math display="block"> <mrow> <mtable> <mtr> <mtd columnalign="right"> <mrow> <mtext>Vol</mtext> <mrow> <mo stretchy="false">(</mo> <msup> <mi>M</mi> <mi>n</mi> </msup> <mo stretchy="false">)</mo> </mrow> <mo>≥</mo> <mfrac> <mrow> <mi>n</mi> <mo>+</mo> <mn>1</mn> </mrow> <mrow> <mi>n</mi> <mo>+</mo> <mn>2</mn> </mrow> </mfrac> <msub> <mo>∫</mo> <mi>M</mi> </msub> <mfenced close=")" open="("> <mn>1</mn> <mo>+</mo> <msubsup> <mi>φ</mi> <mrow> <mi>p</mi> </mrow> <mn>2</mn> </msubsup> </mfenced> <mo>≥</mo> <mi>m</mi> <mtext>Vol</mtext> <mrow> <mo stretchy="false">(</mo> <msup> <mrow> <mi mathvariant="double-struck">S</mi> </mrow> <mi>n</mi> </msup> <mo stretchy="false">)</mo> </mrow> <mo>,</mo> </mrow> </mtd> </mtr> </mtable> </mrow> </math></EquationSource> </Equation>where <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(\varphi _{p}(x):=\langle f(x),p\rangle \)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mi>φ</mi> <mi>p</mi> </msub> <mrow> <mo stretchy="false">(</mo> <mi>x</mi> <mo stretchy="false">)</mo> </mrow> <mo>:</mo> <mo>=</mo> <mrow> <mo stretchy="false">⟨</mo> <mi>f</mi> <mrow> <mo stretchy="false">(</mo> <mi>x</mi> <mo stretchy="false">)</mo> </mrow> <mo>,</mo> <mi>p</mi> <mo stretchy="false">⟩</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation> is the height function in direction <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(p\in f(M)\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>p</mi> <mo>∈</mo> <mi>f</mi> <mo stretchy="false">(</mo> <mi>M</mi> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation>, <i>m</i> denotes the multiplicity of <InlineEquation ID="IEq5"> <EquationSource Format="TEX">\(p\in f(M)\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>p</mi> <mo>∈</mo> <mi>f</mi> <mo stretchy="false">(</mo> <mi>M</mi> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation> and <InlineEquation ID="IEq6"> <EquationSource Format="TEX">\(\textrm{Vol}\)</EquationSource> <EquationSource Format="MATHML"><math> <mtext>Vol</mtext> </math></EquationSource> </InlineEquation> denotes the Riemannian volume functional, and each equality holds if and only if <i>M</i> is totally geodesic. As an application, if the volume of <InlineEquation ID="IEq7"> <EquationSource Format="TEX">\(M^n\)</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mi>M</mi> <mi>n</mi> </msup> </math></EquationSource> </InlineEquation> is less than or equal to the volume of any <i>n</i>-dimensional minimal Clifford torus, then <InlineEquation ID="IEq8"> <EquationSource Format="TEX">\(M^n\)</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mi>M</mi> <mi>n</mi> </msup> </math></EquationSource> </InlineEquation> must be embedded, verifying the non-embedded case of Yau’s conjecture. In addition, we also get volume gaps for minimal hypersurfaces with constant scalar curvature, improving Cheng–Li–Yau’s classical volume gap in this case. Some other volume gaps and related pinching rigidities are also obtained.</p>

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Volume Gap for Minimal Submanifolds in Spheres

  • Jianquan Ge,
  • Fagui Li

摘要

For a closed minimal submanifold in the unit sphere \((n<N)\) ( n < N ) , we prove \(\begin{aligned} \textrm{Vol}(M^n) \ge \frac{n+1}{n+2} \int _{M}\left( 1+\varphi _{p}^2\right) \ge m\textrm{Vol}(\mathbb {S}^{n}), \end{aligned}\) Vol ( M n ) n + 1 n + 2 M 1 + φ p 2 m Vol ( S n ) , where \(\varphi _{p}(x):=\langle f(x),p\rangle \) φ p ( x ) : = f ( x ) , p is the height function in direction \(p\in f(M)\) p f ( M ) , m denotes the multiplicity of \(p\in f(M)\) p f ( M ) and \(\textrm{Vol}\) Vol denotes the Riemannian volume functional, and each equality holds if and only if M is totally geodesic. As an application, if the volume of \(M^n\) M n is less than or equal to the volume of any n-dimensional minimal Clifford torus, then \(M^n\) M n must be embedded, verifying the non-embedded case of Yau’s conjecture. In addition, we also get volume gaps for minimal hypersurfaces with constant scalar curvature, improving Cheng–Li–Yau’s classical volume gap in this case. Some other volume gaps and related pinching rigidities are also obtained.