<p>Given <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10711_2025_985_Article_IEq1.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="116" /> </InlineMediaObject> <EquationSource Format="TEX">\(g \in \mathbb N \cup \{0, \infty \}\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>g</mi> <mo>∈</mo> <mi mathvariant="double-struck">N</mi> <mo>∪</mo> <mo stretchy="false">{</mo> <mn>0</mn> <mo>,</mo> <mi>∞</mi> <mo stretchy="false">}</mo> </mrow> </math></EquationSource> </InlineEquation>, let <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10711_2025_985_Article_IEq2.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="20" /> </InlineMediaObject> <EquationSource Format="TEX">\(\Sigma _g\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi mathvariant="normal">Σ</mi> <mi>g</mi> </msub> </math></EquationSource> </InlineEquation> denote the closed surface of genus <i>g</i> with a Cantor set removed, if <InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10711_2025_985_Article_IEq3.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="53" /> </InlineMediaObject> <EquationSource Format="TEX">\(g&lt;\infty \)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>g</mi> <mo>&lt;</mo> <mi>∞</mi> </mrow> </math></EquationSource> </InlineEquation>; or the blooming Cantor tree, when <InlineEquation ID="IEq4"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10711_2025_985_Article_IEq4.gif" Format="GIF" Height="12" Rendition="HTML" Resolution="72" Type="Linedraw" Width="52" /> </InlineMediaObject> <EquationSource Format="TEX">\(g= \infty \)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>g</mi> <mo>=</mo> <mi>∞</mi> </mrow> </math></EquationSource> </InlineEquation>. We construct a family <InlineEquation ID="IEq5"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10711_2025_985_Article_IEq5.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="44" /> </InlineMediaObject> <EquationSource Format="TEX">\(\mathfrak B(H)\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="fraktur">B</mi> <mo stretchy="false">(</mo> <mi>H</mi> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation> of subgroups of <InlineEquation ID="IEq6"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10711_2025_985_Article_IEq6.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="67" /> </InlineMediaObject> <EquationSource Format="TEX">\({{\,\textrm{Map}\,}}(\Sigma _g)\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mrow> <mspace width="0.166667em" /> <mtext>Map</mtext> <mspace width="0.166667em" /> </mrow> <mo stretchy="false">(</mo> <msub> <mi mathvariant="normal">Σ</mi> <mi>g</mi> </msub> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation> whose elements preserve a <i>block decomposition</i> of <InlineEquation ID="IEq7"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10711_2025_985_Article_IEq7.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="20" /> </InlineMediaObject> <EquationSource Format="TEX">\(\Sigma _g\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi mathvariant="normal">Σ</mi> <mi>g</mi> </msub> </math></EquationSource> </InlineEquation>, and <i>eventually like act</i> like an element of <i>H</i>, where <i>H</i> is a prescribed subgroup of the mapping class group of the block. The group <InlineEquation ID="IEq8"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10711_2025_985_Article_IEq8.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="44" /> </InlineMediaObject> <EquationSource Format="TEX">\(\mathfrak B(H)\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="fraktur">B</mi> <mo stretchy="false">(</mo> <mi>H</mi> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation> surjects onto an appropriate symmetric Thompson group of Farley–Hughes; in particular, it answers positively. Our main result asserts that <InlineEquation ID="IEq9"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10711_2025_985_Article_IEq9.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="44" /> </InlineMediaObject> <EquationSource Format="TEX">\(\mathfrak B(H)\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="fraktur">B</mi> <mo stretchy="false">(</mo> <mi>H</mi> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation> is of type <InlineEquation ID="IEq10"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10711_2025_985_Article_IEq10.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="21" /> </InlineMediaObject> <EquationSource Format="TEX">\(F_n\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>F</mi> <mi>n</mi> </msub> </math></EquationSource> </InlineEquation> if and only if <i>H</i> is. As a consequence, for every <InlineEquation ID="IEq11"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10711_2025_985_Article_IEq11.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="116" /> </InlineMediaObject> <EquationSource Format="TEX">\(g\in \mathbb N \cup \{0, \infty \}\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>g</mi> <mo>∈</mo> <mi mathvariant="double-struck">N</mi> <mo>∪</mo> <mo stretchy="false">{</mo> <mn>0</mn> <mo>,</mo> <mi>∞</mi> <mo stretchy="false">}</mo> </mrow> </math></EquationSource> </InlineEquation> and every <InlineEquation ID="IEq12"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10711_2025_985_Article_IEq12.gif" Format="GIF" Height="15" Rendition="HTML" Resolution="72" Type="Linedraw" Width="43" /> </InlineMediaObject> <EquationSource Format="TEX">\(n\ge 1\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>n</mi> <mo>≥</mo> <mn>1</mn> </mrow> </math></EquationSource> </InlineEquation>, we construct a subgroup <InlineEquation ID="IEq13"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10711_2025_985_Article_IEq13.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="106" /> </InlineMediaObject> <EquationSource Format="TEX">\(G &lt;{{\,\textrm{Map}\,}}(\Sigma _g)\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>G</mi> <mo>&lt;</mo> <mrow> <mspace width="0.166667em" /> <mtext>Map</mtext> <mspace width="0.166667em" /> </mrow> <mo stretchy="false">(</mo> <msub> <mi mathvariant="normal">Σ</mi> <mi>g</mi> </msub> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation> that is of type <InlineEquation ID="IEq14"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10711_2025_985_Article_IEq14.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="21" /> </InlineMediaObject> <EquationSource Format="TEX">\(F_n\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>F</mi> <mi>n</mi> </msub> </math></EquationSource> </InlineEquation> but not of type <InlineEquation ID="IEq15"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10711_2025_985_Article_IEq15.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="35" /> </InlineMediaObject> <EquationSource Format="TEX">\(F_{n+1}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>F</mi> <mrow> <mi>n</mi> <mo>+</mo> <mn>1</mn> </mrow> </msub> </math></EquationSource> </InlineEquation>, and which contains the mapping class group of every compact surface of genus <InlineEquation ID="IEq16"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10711_2025_985_Article_IEq16.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="31" /> </InlineMediaObject> <EquationSource Format="TEX">\(\le g\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mo>≤</mo> <mi>g</mi> </mrow> </math></EquationSource> </InlineEquation> and with non-empty boundary.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Block mapping class groups and their finiteness properties

  • J. Aramayona,
  • J. Aroca,
  • M. Cumplido,
  • R. Skipper,
  • X. Wu

摘要

Given \(g \in \mathbb N \cup \{0, \infty \}\) g N { 0 , } , let \(\Sigma _g\) Σ g denote the closed surface of genus g with a Cantor set removed, if \(g<\infty \) g < ; or the blooming Cantor tree, when \(g= \infty \) g = . We construct a family \(\mathfrak B(H)\) B ( H ) of subgroups of \({{\,\textrm{Map}\,}}(\Sigma _g)\) Map ( Σ g ) whose elements preserve a block decomposition of \(\Sigma _g\) Σ g , and eventually like act like an element of H, where H is a prescribed subgroup of the mapping class group of the block. The group \(\mathfrak B(H)\) B ( H ) surjects onto an appropriate symmetric Thompson group of Farley–Hughes; in particular, it answers positively. Our main result asserts that \(\mathfrak B(H)\) B ( H ) is of type \(F_n\) F n if and only if H is. As a consequence, for every \(g\in \mathbb N \cup \{0, \infty \}\) g N { 0 , } and every \(n\ge 1\) n 1 , we construct a subgroup \(G <{{\,\textrm{Map}\,}}(\Sigma _g)\) G < Map ( Σ g ) that is of type \(F_n\) F n but not of type \(F_{n+1}\) F n + 1 , and which contains the mapping class group of every compact surface of genus \(\le g\) g and with non-empty boundary.