有限群中的自同构轨道和元素阶:几乎可解性和Monster

IF 2 4区 数学 Q1 MATHEMATICS
Alexander Bors, Michael Giudici, C. Praeger
{"title":"有限群中的自同构轨道和元素阶:几乎可解性和Monster","authors":"Alexander Bors, Michael Giudici, C. Praeger","doi":"10.1090/memo/1427","DOIUrl":null,"url":null,"abstract":"<p>For a finite group <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"upper G\">\n <mml:semantics>\n <mml:mi>G</mml:mi>\n <mml:annotation encoding=\"application/x-tex\">G</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula>, we denote by <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"omega left-parenthesis upper G right-parenthesis\">\n <mml:semantics>\n <mml:mrow>\n <mml:mi>ω<!-- ω --></mml:mi>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:mi>G</mml:mi>\n <mml:mo stretchy=\"false\">)</mml:mo>\n </mml:mrow>\n <mml:annotation encoding=\"application/x-tex\">\\omega (G)</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula> the number of <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"upper A u t left-parenthesis upper G right-parenthesis\">\n <mml:semantics>\n <mml:mrow>\n <mml:mi>A</mml:mi>\n <mml:mi>u</mml:mi>\n <mml:mi>t</mml:mi>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:mi>G</mml:mi>\n <mml:mo stretchy=\"false\">)</mml:mo>\n </mml:mrow>\n <mml:annotation encoding=\"application/x-tex\">Aut(G)</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula>-orbits on <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"upper G\">\n <mml:semantics>\n <mml:mi>G</mml:mi>\n <mml:annotation encoding=\"application/x-tex\">G</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula>, and by <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"o left-parenthesis upper G right-parenthesis\">\n <mml:semantics>\n <mml:mrow>\n <mml:mi>o</mml:mi>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:mi>G</mml:mi>\n <mml:mo stretchy=\"false\">)</mml:mo>\n </mml:mrow>\n <mml:annotation encoding=\"application/x-tex\">o(G)</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula> the number of distinct element orders in <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"upper G\">\n <mml:semantics>\n <mml:mi>G</mml:mi>\n <mml:annotation encoding=\"application/x-tex\">G</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula>. In this paper, we are primarily concerned with the two quantities <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"German d left-parenthesis upper G right-parenthesis colon-equal omega left-parenthesis upper G right-parenthesis minus o left-parenthesis upper G right-parenthesis\">\n <mml:semantics>\n <mml:mrow>\n <mml:mrow class=\"MJX-TeXAtom-ORD\">\n <mml:mi mathvariant=\"fraktur\">d</mml:mi>\n </mml:mrow>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:mi>G</mml:mi>\n <mml:mo stretchy=\"false\">)</mml:mo>\n <mml:mo>≔</mml:mo>\n <mml:mi>ω<!-- ω --></mml:mi>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:mi>G</mml:mi>\n <mml:mo stretchy=\"false\">)</mml:mo>\n <mml:mo>−<!-- − --></mml:mo>\n <mml:mi>o</mml:mi>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:mi>G</mml:mi>\n <mml:mo stretchy=\"false\">)</mml:mo>\n </mml:mrow>\n <mml:annotation encoding=\"application/x-tex\">\\mathfrak {d}(G)≔\\omega (G)-o(G)</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula> and <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"German q left-parenthesis upper G right-parenthesis colon-equal omega left-parenthesis upper G right-parenthesis slash o left-parenthesis upper G right-parenthesis\">\n <mml:semantics>\n <mml:mrow>\n <mml:mrow class=\"MJX-TeXAtom-ORD\">\n <mml:mi mathvariant=\"fraktur\">q</mml:mi>\n </mml:mrow>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:mi>G</mml:mi>\n <mml:mo stretchy=\"false\">)</mml:mo>\n <mml:mo>≔</mml:mo>\n <mml:mi>ω<!-- ω --></mml:mi>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:mi>G</mml:mi>\n <mml:mo stretchy=\"false\">)</mml:mo>\n <mml:mrow class=\"MJX-TeXAtom-ORD\">\n <mml:mo>/</mml:mo>\n </mml:mrow>\n <mml:mi>o</mml:mi>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:mi>G</mml:mi>\n <mml:mo stretchy=\"false\">)</mml:mo>\n </mml:mrow>\n <mml:annotation encoding=\"application/x-tex\">\\mathfrak {q}(G)≔\\omega (G)/o(G)</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula>, each of which may be viewed as a measure for how far <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"upper G\">\n <mml:semantics>\n <mml:mi>G</mml:mi>\n <mml:annotation encoding=\"application/x-tex\">G</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula> is from being an AT-group in the sense of Zhang (that is, a group with <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"omega left-parenthesis upper G right-parenthesis equals o left-parenthesis upper G right-parenthesis\">\n <mml:semantics>\n <mml:mrow>\n <mml:mi>ω<!-- ω --></mml:mi>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:mi>G</mml:mi>\n <mml:mo stretchy=\"false\">)</mml:mo>\n <mml:mo>=</mml:mo>\n <mml:mi>o</mml:mi>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:mi>G</mml:mi>\n <mml:mo stretchy=\"false\">)</mml:mo>\n </mml:mrow>\n <mml:annotation encoding=\"application/x-tex\">\\omega (G)=o(G)</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula>). We show that the index <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"StartAbsoluteValue upper G colon upper R a d left-parenthesis upper G right-parenthesis EndAbsoluteValue\">\n <mml:semantics>\n <mml:mrow>\n <mml:mrow class=\"MJX-TeXAtom-ORD\">\n <mml:mo stretchy=\"false\">|</mml:mo>\n </mml:mrow>\n <mml:mi>G</mml:mi>\n <mml:mo>:</mml:mo>\n <mml:mi>R</mml:mi>\n <mml:mi>a</mml:mi>\n <mml:mi>d</mml:mi>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:mi>G</mml:mi>\n <mml:mo stretchy=\"false\">)</mml:mo>\n <mml:mrow class=\"MJX-TeXAtom-ORD\">\n <mml:mo stretchy=\"false\">|</mml:mo>\n </mml:mrow>\n </mml:mrow>\n <mml:annotation encoding=\"application/x-tex\">|G:Rad(G)|</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula> of the soluble radical <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"upper R a d left-parenthesis upper G right-parenthesis\">\n <mml:semantics>\n <mml:mrow>\n <mml:mi>R</mml:mi>\n <mml:mi>a</mml:mi>\n <mml:mi>d</mml:mi>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:mi>G</mml:mi>\n <mml:mo stretchy=\"false\">)</mml:mo>\n </mml:mrow>\n <mml:annotation encoding=\"application/x-tex\">Rad(G)</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula> of <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"upper G\">\n <mml:semantics>\n <mml:mi>G</mml:mi>\n <mml:annotation encoding=\"application/x-tex\">G</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula> can be bounded from above both by a function in <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"German d left-parenthesis upper G right-parenthesis\">\n <mml:semantics>\n <mml:mrow>\n <mml:mrow class=\"MJX-TeXAtom-ORD\">\n <mml:mi mathvariant=\"fraktur\">d</mml:mi>\n </mml:mrow>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:mi>G</mml:mi>\n <mml:mo stretchy=\"false\">)</mml:mo>\n </mml:mrow>\n <mml:annotation encoding=\"application/x-tex\">\\mathfrak {d}(G)</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula> and by a function in <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"German q left-parenthesis upper G right-parenthesis\">\n <mml:semantics>\n <mml:mrow>\n <mml:mrow class=\"MJX-TeXAtom-ORD\">\n <mml:mi mathvariant=\"fraktur\">q</mml:mi>\n </mml:mrow>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:mi>G</mml:mi>\n <mml:mo stretchy=\"false\">)</mml:mo>\n </mml:mrow>\n <mml:annotation encoding=\"application/x-tex\">\\mathfrak {q}(G)</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula> and <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"o left-parenthesis upper R a d left-parenthesis upper G right-parenthesis right-parenthesis\">\n <mml:semantics>\n <mml:mrow>\n <mml:mi>o</mml:mi>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:mi>R</mml:mi>\n <mml:mi>a</mml:mi>\n <mml:mi>d</mml:mi>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:mi>G</mml:mi>\n <mml:mo stretchy=\"false\">)</mml:mo>\n <mml:mo stretchy=\"false\">)</mml:mo>\n </mml:mrow>\n <mml:annotation encoding=\"application/x-tex\">o(Rad(G))</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula>. We also obtain a curious quantitative characterisation of the Fischer-Griess Monster group <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"upper M\">\n <mml:semantics>\n <mml:mi>M</mml:mi>\n <mml:annotation encoding=\"application/x-tex\">M</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula>.</p>","PeriodicalId":49828,"journal":{"name":"Memoirs of the American Mathematical Society","volume":" ","pages":""},"PeriodicalIF":2.0000,"publicationDate":"2019-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":"{\"title\":\"Automorphism Orbits and Element Orders in Finite Groups: Almost-Solubility and the Monster\",\"authors\":\"Alexander Bors, Michael Giudici, C. Praeger\",\"doi\":\"10.1090/memo/1427\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>For a finite group <inline-formula content-type=\\\"math/mathml\\\">\\n<mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"upper G\\\">\\n <mml:semantics>\\n <mml:mi>G</mml:mi>\\n <mml:annotation encoding=\\\"application/x-tex\\\">G</mml:annotation>\\n </mml:semantics>\\n</mml:math>\\n</inline-formula>, we denote by <inline-formula content-type=\\\"math/mathml\\\">\\n<mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"omega left-parenthesis upper G right-parenthesis\\\">\\n <mml:semantics>\\n <mml:mrow>\\n <mml:mi>ω<!-- ω --></mml:mi>\\n <mml:mo stretchy=\\\"false\\\">(</mml:mo>\\n <mml:mi>G</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">)</mml:mo>\\n </mml:mrow>\\n <mml:annotation encoding=\\\"application/x-tex\\\">\\\\omega (G)</mml:annotation>\\n </mml:semantics>\\n</mml:math>\\n</inline-formula> the number of <inline-formula content-type=\\\"math/mathml\\\">\\n<mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"upper A u t left-parenthesis upper G right-parenthesis\\\">\\n <mml:semantics>\\n <mml:mrow>\\n <mml:mi>A</mml:mi>\\n <mml:mi>u</mml:mi>\\n <mml:mi>t</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">(</mml:mo>\\n <mml:mi>G</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">)</mml:mo>\\n </mml:mrow>\\n <mml:annotation encoding=\\\"application/x-tex\\\">Aut(G)</mml:annotation>\\n </mml:semantics>\\n</mml:math>\\n</inline-formula>-orbits on <inline-formula content-type=\\\"math/mathml\\\">\\n<mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"upper G\\\">\\n <mml:semantics>\\n <mml:mi>G</mml:mi>\\n <mml:annotation encoding=\\\"application/x-tex\\\">G</mml:annotation>\\n </mml:semantics>\\n</mml:math>\\n</inline-formula>, and by <inline-formula content-type=\\\"math/mathml\\\">\\n<mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"o left-parenthesis upper G right-parenthesis\\\">\\n <mml:semantics>\\n <mml:mrow>\\n <mml:mi>o</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">(</mml:mo>\\n <mml:mi>G</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">)</mml:mo>\\n </mml:mrow>\\n <mml:annotation encoding=\\\"application/x-tex\\\">o(G)</mml:annotation>\\n </mml:semantics>\\n</mml:math>\\n</inline-formula> the number of distinct element orders in <inline-formula content-type=\\\"math/mathml\\\">\\n<mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"upper G\\\">\\n <mml:semantics>\\n <mml:mi>G</mml:mi>\\n <mml:annotation encoding=\\\"application/x-tex\\\">G</mml:annotation>\\n </mml:semantics>\\n</mml:math>\\n</inline-formula>. In this paper, we are primarily concerned with the two quantities <inline-formula content-type=\\\"math/mathml\\\">\\n<mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"German d left-parenthesis upper G right-parenthesis colon-equal omega left-parenthesis upper G right-parenthesis minus o left-parenthesis upper G right-parenthesis\\\">\\n <mml:semantics>\\n <mml:mrow>\\n <mml:mrow class=\\\"MJX-TeXAtom-ORD\\\">\\n <mml:mi mathvariant=\\\"fraktur\\\">d</mml:mi>\\n </mml:mrow>\\n <mml:mo stretchy=\\\"false\\\">(</mml:mo>\\n <mml:mi>G</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">)</mml:mo>\\n <mml:mo>≔</mml:mo>\\n <mml:mi>ω<!-- ω --></mml:mi>\\n <mml:mo stretchy=\\\"false\\\">(</mml:mo>\\n <mml:mi>G</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">)</mml:mo>\\n <mml:mo>−<!-- − --></mml:mo>\\n <mml:mi>o</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">(</mml:mo>\\n <mml:mi>G</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">)</mml:mo>\\n </mml:mrow>\\n <mml:annotation encoding=\\\"application/x-tex\\\">\\\\mathfrak {d}(G)≔\\\\omega (G)-o(G)</mml:annotation>\\n </mml:semantics>\\n</mml:math>\\n</inline-formula> and <inline-formula content-type=\\\"math/mathml\\\">\\n<mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"German q left-parenthesis upper G right-parenthesis colon-equal omega left-parenthesis upper G right-parenthesis slash o left-parenthesis upper G right-parenthesis\\\">\\n <mml:semantics>\\n <mml:mrow>\\n <mml:mrow class=\\\"MJX-TeXAtom-ORD\\\">\\n <mml:mi mathvariant=\\\"fraktur\\\">q</mml:mi>\\n </mml:mrow>\\n <mml:mo stretchy=\\\"false\\\">(</mml:mo>\\n <mml:mi>G</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">)</mml:mo>\\n <mml:mo>≔</mml:mo>\\n <mml:mi>ω<!-- ω --></mml:mi>\\n <mml:mo stretchy=\\\"false\\\">(</mml:mo>\\n <mml:mi>G</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">)</mml:mo>\\n <mml:mrow class=\\\"MJX-TeXAtom-ORD\\\">\\n <mml:mo>/</mml:mo>\\n </mml:mrow>\\n <mml:mi>o</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">(</mml:mo>\\n <mml:mi>G</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">)</mml:mo>\\n </mml:mrow>\\n <mml:annotation encoding=\\\"application/x-tex\\\">\\\\mathfrak {q}(G)≔\\\\omega (G)/o(G)</mml:annotation>\\n </mml:semantics>\\n</mml:math>\\n</inline-formula>, each of which may be viewed as a measure for how far <inline-formula content-type=\\\"math/mathml\\\">\\n<mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"upper G\\\">\\n <mml:semantics>\\n <mml:mi>G</mml:mi>\\n <mml:annotation encoding=\\\"application/x-tex\\\">G</mml:annotation>\\n </mml:semantics>\\n</mml:math>\\n</inline-formula> is from being an AT-group in the sense of Zhang (that is, a group with <inline-formula content-type=\\\"math/mathml\\\">\\n<mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"omega left-parenthesis upper G right-parenthesis equals o left-parenthesis upper G right-parenthesis\\\">\\n <mml:semantics>\\n <mml:mrow>\\n <mml:mi>ω<!-- ω --></mml:mi>\\n <mml:mo stretchy=\\\"false\\\">(</mml:mo>\\n <mml:mi>G</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">)</mml:mo>\\n <mml:mo>=</mml:mo>\\n <mml:mi>o</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">(</mml:mo>\\n <mml:mi>G</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">)</mml:mo>\\n </mml:mrow>\\n <mml:annotation encoding=\\\"application/x-tex\\\">\\\\omega (G)=o(G)</mml:annotation>\\n </mml:semantics>\\n</mml:math>\\n</inline-formula>). We show that the index <inline-formula content-type=\\\"math/mathml\\\">\\n<mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"StartAbsoluteValue upper G colon upper R a d left-parenthesis upper G right-parenthesis EndAbsoluteValue\\\">\\n <mml:semantics>\\n <mml:mrow>\\n <mml:mrow class=\\\"MJX-TeXAtom-ORD\\\">\\n <mml:mo stretchy=\\\"false\\\">|</mml:mo>\\n </mml:mrow>\\n <mml:mi>G</mml:mi>\\n <mml:mo>:</mml:mo>\\n <mml:mi>R</mml:mi>\\n <mml:mi>a</mml:mi>\\n <mml:mi>d</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">(</mml:mo>\\n <mml:mi>G</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">)</mml:mo>\\n <mml:mrow class=\\\"MJX-TeXAtom-ORD\\\">\\n <mml:mo stretchy=\\\"false\\\">|</mml:mo>\\n </mml:mrow>\\n </mml:mrow>\\n <mml:annotation encoding=\\\"application/x-tex\\\">|G:Rad(G)|</mml:annotation>\\n </mml:semantics>\\n</mml:math>\\n</inline-formula> of the soluble radical <inline-formula content-type=\\\"math/mathml\\\">\\n<mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"upper R a d left-parenthesis upper G right-parenthesis\\\">\\n <mml:semantics>\\n <mml:mrow>\\n <mml:mi>R</mml:mi>\\n <mml:mi>a</mml:mi>\\n <mml:mi>d</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">(</mml:mo>\\n <mml:mi>G</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">)</mml:mo>\\n </mml:mrow>\\n <mml:annotation encoding=\\\"application/x-tex\\\">Rad(G)</mml:annotation>\\n </mml:semantics>\\n</mml:math>\\n</inline-formula> of <inline-formula content-type=\\\"math/mathml\\\">\\n<mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"upper G\\\">\\n <mml:semantics>\\n <mml:mi>G</mml:mi>\\n <mml:annotation encoding=\\\"application/x-tex\\\">G</mml:annotation>\\n </mml:semantics>\\n</mml:math>\\n</inline-formula> can be bounded from above both by a function in <inline-formula content-type=\\\"math/mathml\\\">\\n<mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"German d left-parenthesis upper G right-parenthesis\\\">\\n <mml:semantics>\\n <mml:mrow>\\n <mml:mrow class=\\\"MJX-TeXAtom-ORD\\\">\\n <mml:mi mathvariant=\\\"fraktur\\\">d</mml:mi>\\n </mml:mrow>\\n <mml:mo stretchy=\\\"false\\\">(</mml:mo>\\n <mml:mi>G</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">)</mml:mo>\\n </mml:mrow>\\n <mml:annotation encoding=\\\"application/x-tex\\\">\\\\mathfrak {d}(G)</mml:annotation>\\n </mml:semantics>\\n</mml:math>\\n</inline-formula> and by a function in <inline-formula content-type=\\\"math/mathml\\\">\\n<mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"German q left-parenthesis upper G right-parenthesis\\\">\\n <mml:semantics>\\n <mml:mrow>\\n <mml:mrow class=\\\"MJX-TeXAtom-ORD\\\">\\n <mml:mi mathvariant=\\\"fraktur\\\">q</mml:mi>\\n </mml:mrow>\\n <mml:mo stretchy=\\\"false\\\">(</mml:mo>\\n <mml:mi>G</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">)</mml:mo>\\n </mml:mrow>\\n <mml:annotation encoding=\\\"application/x-tex\\\">\\\\mathfrak {q}(G)</mml:annotation>\\n </mml:semantics>\\n</mml:math>\\n</inline-formula> and <inline-formula content-type=\\\"math/mathml\\\">\\n<mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"o left-parenthesis upper R a d left-parenthesis upper G right-parenthesis right-parenthesis\\\">\\n <mml:semantics>\\n <mml:mrow>\\n <mml:mi>o</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">(</mml:mo>\\n <mml:mi>R</mml:mi>\\n <mml:mi>a</mml:mi>\\n <mml:mi>d</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">(</mml:mo>\\n <mml:mi>G</mml:mi>\\n <mml:mo stretchy=\\\"false\\\">)</mml:mo>\\n <mml:mo stretchy=\\\"false\\\">)</mml:mo>\\n </mml:mrow>\\n <mml:annotation encoding=\\\"application/x-tex\\\">o(Rad(G))</mml:annotation>\\n </mml:semantics>\\n</mml:math>\\n</inline-formula>. We also obtain a curious quantitative characterisation of the Fischer-Griess Monster group <inline-formula content-type=\\\"math/mathml\\\">\\n<mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"upper M\\\">\\n <mml:semantics>\\n <mml:mi>M</mml:mi>\\n <mml:annotation encoding=\\\"application/x-tex\\\">M</mml:annotation>\\n </mml:semantics>\\n</mml:math>\\n</inline-formula>.</p>\",\"PeriodicalId\":49828,\"journal\":{\"name\":\"Memoirs of the American Mathematical Society\",\"volume\":\" \",\"pages\":\"\"},\"PeriodicalIF\":2.0000,\"publicationDate\":\"2019-10-25\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"1\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Memoirs of the American Mathematical Society\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://doi.org/10.1090/memo/1427\",\"RegionNum\":4,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Memoirs of the American Mathematical Society","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1090/memo/1427","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 1

摘要

对于有限群G G,我们用ω(G)\omega(G)表示G G上a u t(G)Aut(G。在本文中,我们主要关注两个量d(G)ω(G)−o(G)\mathfrak{d}(G)≔\omega(G)-o(G)和q(G)(G) ,它们中的每一个都可以被视为G离张意义上的AT群(即ω(G)=o(G)\ω(G。我们证明了G的可溶性自由基R a d(G)Rad(G)的指数|G:R a dq(G)\mathfrak{q}(G)和o(R a d(G))o(Rad(G)。我们还获得了Fischer Griess Monster群M M的一个奇怪的定量刻画。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Automorphism Orbits and Element Orders in Finite Groups: Almost-Solubility and the Monster

For a finite group G G , we denote by ω ( G ) \omega (G) the number of A u t ( G ) Aut(G) -orbits on G G , and by o ( G ) o(G) the number of distinct element orders in G G . In this paper, we are primarily concerned with the two quantities d ( G ) ω ( G ) o ( G ) \mathfrak {d}(G)≔\omega (G)-o(G) and q ( G ) ω ( G ) / o ( G ) \mathfrak {q}(G)≔\omega (G)/o(G) , each of which may be viewed as a measure for how far G G is from being an AT-group in the sense of Zhang (that is, a group with ω ( G ) = o ( G ) \omega (G)=o(G) ). We show that the index | G : R a d ( G ) | |G:Rad(G)| of the soluble radical R a d ( G ) Rad(G) of G G can be bounded from above both by a function in d ( G ) \mathfrak {d}(G) and by a function in q ( G ) \mathfrak {q}(G) and o ( R a d ( G ) ) o(Rad(G)) . We also obtain a curious quantitative characterisation of the Fischer-Griess Monster group M M .

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来源期刊
CiteScore
3.50
自引率
5.30%
发文量
39
审稿时长
>12 weeks
期刊介绍: Memoirs of the American Mathematical Society is devoted to the publication of research in all areas of pure and applied mathematics. The Memoirs is designed particularly to publish long papers or groups of cognate papers in book form, and is under the supervision of the Editorial Committee of the AMS journal Transactions of the AMS. To be accepted by the editorial board, manuscripts must be correct, new, and significant. Further, they must be well written and of interest to a substantial number of mathematicians.
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