Simple groups of the same order











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I heard that there are no 3 nonisomorphic simple groups of the same order.




Question: Is there an elementary proof of this?




In case this is not the case, here a modified question:




Question: Is there an elementary proof that there are not $m$ nonisomorphic simple groups of the same order with $m geq 4$ as small as possible?











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  • A related question: How spread out are the (non-abelian) simple groups in terms of their orders? What are some "near misses"? For example, 168-60 is already quite small. Are there smaller differences, perhaps scaling to account for size?
    – David Richter
    Dec 7 at 17:17















up vote
7
down vote

favorite
1












I heard that there are no 3 nonisomorphic simple groups of the same order.




Question: Is there an elementary proof of this?




In case this is not the case, here a modified question:




Question: Is there an elementary proof that there are not $m$ nonisomorphic simple groups of the same order with $m geq 4$ as small as possible?











share|cite|improve this question
























  • A related question: How spread out are the (non-abelian) simple groups in terms of their orders? What are some "near misses"? For example, 168-60 is already quite small. Are there smaller differences, perhaps scaling to account for size?
    – David Richter
    Dec 7 at 17:17













up vote
7
down vote

favorite
1









up vote
7
down vote

favorite
1






1





I heard that there are no 3 nonisomorphic simple groups of the same order.




Question: Is there an elementary proof of this?




In case this is not the case, here a modified question:




Question: Is there an elementary proof that there are not $m$ nonisomorphic simple groups of the same order with $m geq 4$ as small as possible?











share|cite|improve this question















I heard that there are no 3 nonisomorphic simple groups of the same order.




Question: Is there an elementary proof of this?




In case this is not the case, here a modified question:




Question: Is there an elementary proof that there are not $m$ nonisomorphic simple groups of the same order with $m geq 4$ as small as possible?








gr.group-theory finite-groups






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edited Dec 7 at 15:57









Jim Humphreys

41.4k491188




41.4k491188










asked Dec 7 at 14:53









Mare

3,57121231




3,57121231












  • A related question: How spread out are the (non-abelian) simple groups in terms of their orders? What are some "near misses"? For example, 168-60 is already quite small. Are there smaller differences, perhaps scaling to account for size?
    – David Richter
    Dec 7 at 17:17


















  • A related question: How spread out are the (non-abelian) simple groups in terms of their orders? What are some "near misses"? For example, 168-60 is already quite small. Are there smaller differences, perhaps scaling to account for size?
    – David Richter
    Dec 7 at 17:17
















A related question: How spread out are the (non-abelian) simple groups in terms of their orders? What are some "near misses"? For example, 168-60 is already quite small. Are there smaller differences, perhaps scaling to account for size?
– David Richter
Dec 7 at 17:17




A related question: How spread out are the (non-abelian) simple groups in terms of their orders? What are some "near misses"? For example, 168-60 is already quite small. Are there smaller differences, perhaps scaling to account for size?
– David Richter
Dec 7 at 17:17










1 Answer
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13
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accepted










No, there are no known proofs of any results of this type that do not rely on the complete classification of finite simple groups



In particular, the result of Pyber (1993) giving an upper bound on the number of isomorphism classes of finite groups of order $n$ (see Jack Schmidt's answer to this question for details) could only be incorrect if there were vast numbers of isomorphism classes of simple groups of the same order, but it still relies on the classification.






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    1 Answer
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    1 Answer
    1






    active

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    active

    oldest

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    up vote
    13
    down vote



    accepted










    No, there are no known proofs of any results of this type that do not rely on the complete classification of finite simple groups



    In particular, the result of Pyber (1993) giving an upper bound on the number of isomorphism classes of finite groups of order $n$ (see Jack Schmidt's answer to this question for details) could only be incorrect if there were vast numbers of isomorphism classes of simple groups of the same order, but it still relies on the classification.






    share|cite|improve this answer



























      up vote
      13
      down vote



      accepted










      No, there are no known proofs of any results of this type that do not rely on the complete classification of finite simple groups



      In particular, the result of Pyber (1993) giving an upper bound on the number of isomorphism classes of finite groups of order $n$ (see Jack Schmidt's answer to this question for details) could only be incorrect if there were vast numbers of isomorphism classes of simple groups of the same order, but it still relies on the classification.






      share|cite|improve this answer

























        up vote
        13
        down vote



        accepted







        up vote
        13
        down vote



        accepted






        No, there are no known proofs of any results of this type that do not rely on the complete classification of finite simple groups



        In particular, the result of Pyber (1993) giving an upper bound on the number of isomorphism classes of finite groups of order $n$ (see Jack Schmidt's answer to this question for details) could only be incorrect if there were vast numbers of isomorphism classes of simple groups of the same order, but it still relies on the classification.






        share|cite|improve this answer














        No, there are no known proofs of any results of this type that do not rely on the complete classification of finite simple groups



        In particular, the result of Pyber (1993) giving an upper bound on the number of isomorphism classes of finite groups of order $n$ (see Jack Schmidt's answer to this question for details) could only be incorrect if there were vast numbers of isomorphism classes of simple groups of the same order, but it still relies on the classification.







        share|cite|improve this answer














        share|cite|improve this answer



        share|cite|improve this answer








        edited Dec 7 at 15:54









        Jim Humphreys

        41.4k491188




        41.4k491188










        answered Dec 7 at 15:09









        Derek Holt

        26.4k461108




        26.4k461108






























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