广义超特殊p-群的自同构群Ⅲ

确定了广义超特殊p-群G的自同构群的结构.设|G|=p~(2n+m),|■G|=p~m,其中n≥1,m≥2,Aut_fG是AutG中平凡地作用在Frat G上的元素形成的正规子群,则(1)当G的幂指数是p~m时,(i)如果p是奇素数,那么AutG/AutfG≌Z_((p-1)p~(m-2)),并且AutfG/InnG≌Sp(2n,p)×Zp.(ii)如果p=2,那么AutG=Aut_fG(若m=2)或者AutG/AutfG≌Z_(2~(m-3))×Z_2(若m≥3),并且AutfG/InnG≌Sp(2n,2)×Z_2.(2)当G的幂指数是p~(m+1)时,(i)如果p是奇素数,那么AutG=〈θ〉■Aut_fG,其中θ的阶是(p-1)p~(m-1),且Aut_f G/Inn G≌K■Sp(2n-2,p),其中K是p~(2n-1)阶超特殊p-群.(ii)如果p=2,那么AutG=〈θ_1,θ_2〉■Aut_fG,其中〈θ_1,θ_2〉=〈θ_1〉×〈θ_2〉≌Z_(2~(m-2))×Z_2,并且Aut_fG/Inn G≌K×Sp(2n-2,2),其中K是2~(2n-1)阶初等Abel 2-群.特别地,当n=1时...     

The automorphism group of a generalized extraspecial p-group

In this paper, the automorphism group of a generalized extraspecial p-group G is determined, where p is a prime number. Assume that |G| = p 2n+m and |ζG| = p m , where n 1 and m 2. (1) When p is odd, let Aut G G = {α∈ AutG | α acts trivially on G }. Then Aut G G⊿AutG and AutG/Aut G G≌Z p-1 . Furthermore, (i) If G is of exponent p m , then Aut G G/InnG≌Sp(2n, p) × Z p m-1 . (ii) If G is of exponent p m+1 , then Aut G G/InnG≌ (K Sp(2n-2, p))×Z p m-1 , where K is an extraspecial p-group of order p 2n-1 . In particular, Aut G G/InnG≌ Z p × Z p m-1 when n = 1. (2) When p = 2, then, (i) If G is of exponent 2 m , then AutG≌ Sp(2n, 2) × Z 2 × Z 2 m-2 . In particular, when n = 1, |AutG| = 3 · 2 m+2 . None of the Sylow subgroups of AutG is normal, and each of the Sylow 2-subgroups of AutG is isomorphic to H K, where H = Z 2 × Z 2 × Z 2 × Z 2 m-2 , K = Z 2 . (ii) If G is of exponent 2 m+1 , then AutG≌ (I Sp(2n-2, 2)) × Z 2 × Z 2 m-2 , where I is an elementary abelian 2-group of order 2 2n-1 . In particular, when n = 1, |AutG| = 2 m+2 and AutG≌ H K, where H = Z 2 × Z 2 × Z 2 m-1 , K = Z 2 .     

广义超特殊p-群的自同构群(Ⅱ)

重新确定了广义超特殊p-群G的自同构群的结构.设|G|=p~(2n+m),|ζG|=p~m,其中n≥1,m≥2,Aut_cG是AutG中平凡地作用在ζG上的元素形成的正规子群,则(i)若p是奇素数,则AutG=〈θ〉×Aut_cG,其中θ的阶是(p-1)p~(m-1);若p=2,则AutG=〈θ_1,θ_2〉×Aut_cG,其中〈θ_1,θ_2〉=〈θ_1〉×〈θ_2〉≌Z_(2m-2)×Z_2.(ii)如果G的幂指数是p~m,那么Aut_cG/InnG≌Sp(2n,p).(iii)如果G的幂指数是p~(m+1),那么Aut_cG/InnG≌K×Sp(2n-2,p),其中K是p~(2n-1)阶超特殊p-群(若p是奇素数)或者初等Abel 2-群.特别地,当n=1时,Aut_cG/InnG≌Z_p.     

广义超特殊p-群的自同构群

确定了广义超特殊p-群G的自同构群的结构.假设｜G｜=p^2n＋m,｜ζG｜=p^m,其中n≥1,m≥2,（1）当p是奇数时,记AutG＇G={α∈AutG｜α在G上作用平凡},则（i）AutG＇G Aut G,Aut G/AutG＇G=～Zp-1;（ii）如果G的幂指数是p^m,那么AutG＇G/InnG=～Sp（2n,p）×Zp^m-1;（iii）如果G的幂指数是p^m＋1,那么AutG＇G/InnG=～（K×Sp（2n-2,p））×Zp^m-1,其中K是p^2n-1阶超特殊p-群.特别地,当n=1时,AutG＇G/Inn G=～Zp×Zp^m-1.（2）当p=2时,（i）如果G的幂指数是2^m,那么Out G=～Sp（2n,2）×Z2×Z2^m-2.特别地,当n=1时,｜Aut G｜=3·2^m＋2,Aut G的Sylow子群都不是正规子群,并且Aut G的Sylow 2-子群都同构于HK,其中H=Z2×Z2×Z2×Z2^m-2,K=Z2.（ii）如果G的幂指数是2^m＋1,那么OutG=～（ISp（2n2,2））×Z2×Z2^m-2,其中I是一个2^2n-1阶初等Abel 2-群.特别地,当n=1时,｜AutG｜=2^m＋2并且Aut G=～HK,其中H=Z2×Z2×Z2^m-1,K=Z2.     

关于一类中心循环的有限P-群的自同构群

确定了一类中心循环的有限p-群G的自同构群.设G=X_3(p~m)~(*n)*Z_(p~(m+r)),其中m≥1,n≥1和r≥0,并且X_3(p~m)=x,y|x~(p~m)=y~(p~m)=1,[x,y]~(p~m)=1,[x,[x,y]]=[y,[x,y]]=1.Aut_nG表示Aut G中平凡地作用在N上的元素形成的正规子群,其中G'≤N≤ζG,|N|=p~(m+s),0≤s≤r,则(i)如果p是一个奇素数,那么AutG/Aut_nG≌Z_(p~((m+s-1)(p-1))),Aut_nG/InnG≌Sp(2n,Z_(p~m))×Z_(p~(r-s)).(ii)如果p=2,那么AutG/Aut_nG≌H,其中H=1(当m+s=1时)或者Z_(2~(m+s-2))×Z_2(当m+s≥2时).进一步地,Aut_nG/InnG≌K×L,其中K=Sp(2n,Z_(2~m))(当r0时)或者O(2n,Z_(2~m))(当r=0时),L=Z_(2~(r-1))×Z_2(当m=1,s=0,r≥1时)或者Z_(2~(r-s)).     

关于广义超特殊p-群的自同构群

用如下的方式确定了广义超特殊p-群G的自同构群.设|G|=p2n+m,|ζG|=pm,|N|=pl并且G'≤N≤ζG,其中n≥1且m≥2.AutnG表示AutG中平凡地作用在N上的所有自同构形成的正规子群.则(1)当p是奇素数时,AutG/AunG≌Z(p-1)pl-1.进一步地,(i)如果G的幂指数是pm,则Autn...     

U(4,Z)的自同构群(英文)

In this paper,the automorphism group of G is determined,where G is a 4 × 4 upper unitriangular matrix group over Z.Let K be the subgroup of AutG consisting of all elements of AutG which act trivially on G/G,G /ζG and ζG,then （i） InnG ■ K ■ AutG;（ii） AutG/K≌=G₁×D₈×Z₂,where G₁=(a,b,c|a⁴=b²=c²=1,a^b=a^-1,[a,c]= [b,c]=1 ;（iii） K/Inn G≌=Z×Z×Z.     

Automorphisms of a Class of Finite p-groups with a Cyclic Derived Subgroup

Let p be an odd prime,and let k be a nonzero nature number.Suppose that nonabelian group G is a central extension as follows1→G'→G→Z_(p~k)×…×Z_(p~k),where G'≌Z_(p~k),and ζG/G' is a,direct factor of G/G'.Then G is a central product of an extraspecial p~kgroup E and ζG.Let |E|=p~((2n+1)k) and |ζG|=p~((m+1)k).Suppose that the exponents of E and ζG are p~(k+l) and p~(k+r),respectively,where 0≤l,r≤k.Let Aut_(G') G be the normal subgroup of Aut G consisting of all elements of Aut G which act trivially on the derived subgroup G',let Aut_(G/ζG,ζG) G be the normal subgroup of Aut G consisting of all central automorphisms of G which also act trivially on the center ζG and let Aut_(G/ζG,ζG/G') G be the normal subgroup of Aut G consisting of all central automorphisms of G which also act trivially on ζG/G'.Then(ⅰ) The group extension 1→Aut G'→Aut G→Aut G'→1 is split.(ⅱ) Aut_(G') G/Aut_(G/ζG,ζG) G≌G_1 × G_2,where Sp(2n-2,Z_(p~k))■H≤G_1≤Sp(2n,Z_(p~k)),H is an extraspecial p~k-group of order p~((2n-1)k) and(GL(m-1,Z_(p~k))■Z_(p~k)~((m-1))■Z_(p~k)~((m))≤G_2≤GL(m,Z_(p~k))■Z_(p~k)~((m)).In particular,G_1=Sp(2n-2,Z~(p~k))■ H if and only if l=k and r=0;G_1=Sp(2n,Z_(p~x)) if and only if l≤r;G_2=(GL(m-1,Z_(p~k))■ Z_(p~k)~((m-1))■ Z_(p~k)~((m)) if and only if r=k;G_2=GL(m,Z_(p~k))■Z_(p~k)((m)) if and only if r=0.(ⅲ) Aut_(G') G/Aut_( G/ζG,ζG/G') G≌G_1 × G_3,where G_1 is defined in(ⅱ);GL(ml,Z_(p~k))■ Z_(p~k)~((m-1))≤G_3 ≤GL(n,Z_(p~k)).In particular,G_3=GL(m-1,Z_(p~k))■ Z_(p~k)~((m-1)) if and only if r=k;G_3=GL(m,Z_(p~k)) if and only if r=0.(ⅳ) Ant_(G/ζG,ζG/G') G≌ Aut_(G/ζG,ζG/G') G■ Z_(p~k)~((m)),If m=0,then Ant_(G/ζG,ζG/G') G=Inn G≌Z_(p~k)~((2n));If m 0,then Ant_(G/ζG,ζG/G') G≌Z_(p~k)~((2nm))×Z_(p~(k-r))~((2n)),and Aut_(G/ζG,ζG) G/Inn G≌Z_(p~k)~((2n(m-1))× Z_(p~(k-r))~((2n)).     

The Automorphism Group of a Class of Nilpotent Groups with Infinite Cyclic Derived Subgroups

The automorphism group of a class of nilpotent groups with infinite cyclic derived subgroups is determined. Let G be the direct product of a generalized extraspecial Z-group E and a free abelian group A with rank m, where E ={(1 kα_1 kα_2 ··· kα_nα_(n+1) 0 1 0 ··· 0 α_(n+2)...............000...1 α_(2n+1)000...01|αi∈ Z, i = 1, 2,..., 2 n + 1},where k is a positive integer. Let AutG G be the normal subgroup of Aut G consisting of all elements of Aut G which act trivially on the derived subgroup G of G, and AutG/ζ G,ζ GG be the normal subgroup of Aut G consisting of all central automorphisms of G which also act trivially on the center ζ G of G. Then(i) The extension 1→ Aut_(G') G→ AutG→ Aut(G')→ 1 is split.(ii) Aut_(G') G/Aut_(G/ζ G,ζ G)G≌Sp(2 n, Z) ×(GL(m, Z)■(Z~)m).(iii) Aut_(G/ζ G,ζ GG/Inn G)≌(Z_k)~(2n)⊕(Z)~(2nm).     

超特殊Z-群的自同构群

确定了超特殊Z-群的自同构群.设G是超特殊Z-群,即G={(1 α_1 α_2···α_n α_(n+1) 0 1 0···0 α_(n+2) ···0 0 0 ··· 0 α_2n 0 0 0··· 1 α_(2n+1) 0 0 0···1 α_(2n+1) 0 0 0···0 1)|α_j∈Z,j=1,2,3,...,2n+1}Aut_cG是AutG中平凡作用在ζG上的自同构形成的正规子群,则AutG=Aut_cG×Z_2,且1→Z···Z}2N→Aut_cG→Sp(2n,Z)→1是正合列.