<p>Let <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="25_2025_2468_Article_IEq1.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="45" /> </InlineMediaObject> <EquationSource Format="TEX">\(G\ne 1\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>G</mi> <mo>≠</mo> <mn>1</mn> </mrow> </math></EquationSource> </InlineEquation> be a finite group. A subgroup chain <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="25_2025_2468_Article_IEq2.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="288" /> </InlineMediaObject> <EquationSource Format="TEX">\(1=M_0&lt; M_1&lt; \ldots&lt; M_{n-1}&lt; M_n=G\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>1</mn> <mo>=</mo> <msub> <mi>M</mi> <mn>0</mn> </msub> <mo>&lt;</mo> <msub> <mi>M</mi> <mn>1</mn> </msub> <mo>&lt;</mo> <mo>…</mo> <mo>&lt;</mo> <msub> <mi>M</mi> <mrow> <mi>n</mi> <mo>-</mo> <mn>1</mn> </mrow> </msub> <mo>&lt;</mo> <msub> <mi>M</mi> <mi>n</mi> </msub> <mo>=</mo> <mi>G</mi> </mrow> </math></EquationSource> </InlineEquation>, in which <InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="25_2025_2468_Article_IEq3.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="24" /> </InlineMediaObject> <EquationSource Format="TEX">\(M_i\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>M</mi> <mi>i</mi> </msub> </math></EquationSource> </InlineEquation> is a maximal subgroup of <InlineEquation ID="IEq4"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="25_2025_2468_Article_IEq4.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="37" /> </InlineMediaObject> <EquationSource Format="TEX">\(M_{i+1}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>M</mi> <mrow> <mi>i</mi> <mo>+</mo> <mn>1</mn> </mrow> </msub> </math></EquationSource> </InlineEquation> for every <i>i</i>, is called a maximal chain, and <i>n</i> is its length. Every chain is associated with a sequence of positive integers <InlineEquation ID="IEq5"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="25_2025_2468_Article_IEq5.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="16" /> </InlineMediaObject> <EquationSource Format="TEX">\(j_1\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>j</mi> <mn>1</mn> </msub> </math></EquationSource> </InlineEquation>, <InlineEquation ID="IEq6"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="25_2025_2468_Article_IEq6.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="16" /> </InlineMediaObject> <EquationSource Format="TEX">\(j_2\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>j</mi> <mn>2</mn> </msub> </math></EquationSource> </InlineEquation>, ..., <InlineEquation ID="IEq7"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="25_2025_2468_Article_IEq7.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="18" /> </InlineMediaObject> <EquationSource Format="TEX">\(j_n\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>j</mi> <mi>n</mi> </msub> </math></EquationSource> </InlineEquation>, where <InlineEquation ID="IEq8"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="25_2025_2468_Article_IEq8.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="120" /> </InlineMediaObject> <EquationSource Format="TEX">\(j_i=|M_i:M_{i-1}|\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mi>j</mi> <mi>i</mi> </msub> <mo>=</mo> <mrow> <mo stretchy="false">|</mo> <msub> <mi>M</mi> <mi>i</mi> </msub> <mo>:</mo> <msub> <mi>M</mi> <mrow> <mi>i</mi> <mo>-</mo> <mn>1</mn> </mrow> </msub> <mo stretchy="false">|</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation>. If <InlineEquation ID="IEq9"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="25_2025_2468_Article_IEq9.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="133" /> </InlineMediaObject> <EquationSource Format="TEX">\(j_1\le j_2\le \ldots \le j_n\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mi>j</mi> <mn>1</mn> </msub> <mo>≤</mo> <msub> <mi>j</mi> <mn>2</mn> </msub> <mo>≤</mo> <mo>…</mo> <mo>≤</mo> <msub> <mi>j</mi> <mi>n</mi> </msub> </mrow> </math></EquationSource> </InlineEquation> (<InlineEquation ID="IEq10"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="25_2025_2468_Article_IEq10.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="133" /> </InlineMediaObject> <EquationSource Format="TEX">\(j_1\ge j_2\ge \ldots \ge j_n\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mi>j</mi> <mn>1</mn> </msub> <mo>≥</mo> <msub> <mi>j</mi> <mn>2</mn> </msub> <mo>≥</mo> <mo>…</mo> <mo>≥</mo> <msub> <mi>j</mi> <mi>n</mi> </msub> </mrow> </math></EquationSource> </InlineEquation>), then we say that a chain is a &lt;-chain (respectively, &gt;-chain). We prove that a group <i>G</i> is supersolvable if <i>G</i> has two chains of the same length, one of which is a <InlineEquation ID="IEq11"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="25_2025_2468_Article_IEq11.gif" Format="GIF" Height="11" Rendition="HTML" Resolution="72" Type="Linedraw" Width="17" /> </InlineMediaObject> <EquationSource Format="TEX">\({&lt;}\)</EquationSource> <EquationSource Format="MATHML"><math> <mo>&lt;</mo> </math></EquationSource> </InlineEquation>-chain and the other is a &gt;-chain. We classify finite groups in which every maximal chain in every proper subgroup is a &lt;-chain or a &gt;-chain.</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

On Indices of Maximal Chains in Finite Groups

  • Victor S. Monakhov,
  • Irina L. Sokhor

摘要

Let \(G\ne 1\) G 1 be a finite group. A subgroup chain \(1=M_0< M_1< \ldots< M_{n-1}< M_n=G\) 1 = M 0 < M 1 < < M n - 1 < M n = G , in which \(M_i\) M i is a maximal subgroup of \(M_{i+1}\) M i + 1 for every i, is called a maximal chain, and n is its length. Every chain is associated with a sequence of positive integers \(j_1\) j 1 , \(j_2\) j 2 , ..., \(j_n\) j n , where \(j_i=|M_i:M_{i-1}|\) j i = | M i : M i - 1 | . If \(j_1\le j_2\le \ldots \le j_n\) j 1 j 2 j n ( \(j_1\ge j_2\ge \ldots \ge j_n\) j 1 j 2 j n ), then we say that a chain is a <-chain (respectively, >-chain). We prove that a group G is supersolvable if G has two chains of the same length, one of which is a \({<}\) < -chain and the other is a >-chain. We classify finite groups in which every maximal chain in every proper subgroup is a <-chain or a >-chain.