Correction to the Paper - Determination of a Domain in Complex Space by its Automorphism Group

The author offers some corrections to his article which appeared in Vol. 47, No. 3 of this journal.     

On the Automorphism Group of a Semifield of Order 54

The purpose of this article is to determine Aut(A) where A is a semifield of order 5⁴ admitting an automorphism group E ? Z ₂ × Z ₂ acting freely on A.     

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...     

具有4pq阶自同构群的有限群

本文讨论了自同构群阶为4pq(p,q为不同奇素数)的有限群,得出了它们的构造.     

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)).     

The Semi-Arc Automorphism Group of a Graph with Application to Map Enumeration

A map is a connected topological graph cellularly embedded in a surface. For a given graph Γ, its genus distribution of rooted maps and embeddings on orientable and non-orientable surfaces are separately investigated by many researchers. By introducing the concept of a semi-arc automorphism group of a graph and classifying all its embeddings under the action of its semi-arc automorphism group, we find the relations between its genus distribution of rooted maps and genus distribution of embeddings on orientable and non-orientable surfaces, and give some new formulas for the number of rooted maps on a given orientable surface with underlying graph a bouquet of cycles B_n, a closed-end ladder L_n or a Ringel ladder R_n. A general scheme for enumerating unrooted maps on surfaces(orientable or non-orientable) with a given underlying graph is established. Using this scheme, we obtained the closed formulas for the numbers of non-isomorphic maps on orientable or non-orientable surfaces with an underlying bouquet B_n in this paper.     

Automorphism Group of q-Quantum Torus Lie Algebra with q a Root of Unity*

Let α be an automorphism of a ring R. We study the skew Armendariz of Laurent series type rings (α-LA rings), as a generalization of the standard Armendariz condition from polynomials to skew Laurent series. We study on the relationship between the Baerness and p.p. property of a ring R and these of the skew Laurent series ring R[[x, x ^?1; α]], in case R is an α-LA ring. Moreover, we prove that for an α-weakly rigid ring R, R[[x, x ^?1; α]] is a left p.q.-Baer ring if and only if R is left p.q.-Baer and every countable subset of S _?(R) has a generalized countable join in R. Various types of examples of α-LA rings are provided.     

On the Automorphism Group of the First Weyl Algebra

Let A ₁: = 𝕜[t, ?] be the first algebra over a field 𝕜 of characteristic zero. Let Aut_𝕜(A ₁) be the automorphism group of the ring A ₁. One can associate to each right ideal I of A ₁ a subgroup of Aut_𝕜(A ₁) called the isomorphism subgroup of I. In this article, we show that each such isomorphism subgroup is equal to its normalizer. For that, we study when the isomorphism subgroup of a right ideal of A ₁ contains a given isomorphism subgroup.     

（广义）四元数群的自同构群及其全形

该文讨论了一类2^n阶非交换群——（广义）四元数群Q_{2^n}=〈a,b|a^{2^n-1}=1,b^2=a^{2^{n-2}},{b^{-1}ab=a^{-1}〉(n≥3)的自同构群A（Q_{2^n}）与全形H（Q_{2^n}））的置换表示，给出了A（Q_{2^n}））与H（Q_{2^n}））的构造.     

Linear Representations of the Automorphism Group of a Free Group

Let F _n be the free group on n ≥ 2 elements and Aut(F _n ) its group of automorphisms. In this paper we present a rich collection of linear representations of Aut(F _n ) arising through the action of finite-index subgroups of it on relation modules of finite quotient groups of F _n . We show (under certain conditions) that the images of our representations are arithmetic groups. Received: November 2006, Accepted: March 2007     

量子环面李代数的自同构群, 泛中心扩张与导子

C_q:=C_q[x^±1₁, x^±1₂] 为复数域上的量子环面, 其中q≠ 0是一个非单位根, D(C_q) 为C_q的导子李代数. 记L_q 为C_q ㈩ D(C_q)的导出子代数. 该文研究李代数L_q的自同构群, 泛中心扩张和导子李代数.     

量子环面李代数的自同构群,泛中心扩张与导子

Cq=Cq[x1^±1,x2^±1]为复数域上的量子环面，其中q≠0是一个非单位根，D（Cq）为Cq的导子李代数．记Lq为Cq＋D（Cq）的导出子代数．该文研究李代数Lq的自同构群，泛中心扩张和导子李代数．     

Classifying Finite Simple Groups with Respect to the Number of Orbits Under the Action of the Automorphism Group

Abstract

Let ω(G) denote the number of orbits on the finite group G under the action of Aut(G). Using the classification of finite simple groups, we prove that for any positive integer n, there is only a finite number of (non-abelian) finite simple groups G satisfying ω(G) ≤ n. Then we classify all finite simple groups G such that ω(G) ≤ 17. The latter result was obtained by computational means, using the computer algebra system GAP.     

A Note on the Wong-Rosay Theorem in Complex Manifolds

The authors prove a version, in utmost generality, of the Bun Wong-Rosay theorem on a complex manifold M. The essence of the result is that a domain Ω?M with non-compact automorphism group and boundary orbit accumulation point that is strongly pseudoconvex must be biholomorphic to the unit ball in C ⁿ .     

The Bergman Kernel Function and Full Group of Holomorphic Automorphism on a Reinhardt Domain

ＴｈｅＢｅｒｇｍａｎＫｅｒｎｅｌＦｕｎｃｔｉｏｎａｎｄＦｕｌｌＧｒｏｕｐｏｆＨｏｌｏｍｏｒｐｈｉｃＡｕｔｏｍｏｒｐｈｉｓｍｏｎａＲｅｉｎｈａｒｄｔＤｏｍａｉｎＧｕａｎＢｉｎｘｉｎ（管冰辛）ＷａｎｇＡｎ（王安）（Ｄｅｐｔ．ｏｆＭａｔｈ．，Ｃａｐｉｔａｌ...     

Bireflectionality of the Orthogonal Group over a Principal Ideal Domain

ＢｉｒｅｆｌｅｃｔｉｏｎａｌｉｔｙｏｆｔｈｅＯｒｔｈｏｇｏｎａｌＧｒｏｕｐｏｖｅｒａＰｒｉｎｃｉｐａｌＩｄｅａｌＤｏｍａｉｎＣｈｅｎＹｉｈｏｎｇ（陈一宏）（ＤｅｐａｒｔｍｅｎｔｏｆＡｐｐｌｉｅｄＭａｔｈｅｍａｔｉｃｓ，ＢｅｉｊｉｎｇＩｎｓｔｉｔｕｔｅ...     

素特征域上广义Witt李超代数的自同构群

设W是素特征域上无限维或有限维广义Witt李超代数.本文利用W的自然滤过不变性和W的底代数的不变维数性质,证明了W的自同构群AutW同构于W的底代数的容许自同构群,还证明了在此群同构之下,AutW的标准正规列恰好对应W的底代数的容许自同构群的标准正规列,并给出AutW若干较为细致的性质.     

Structure of a Conjugating Automorphism Group

We examine the automorphism group Aut(F _n ) of a free group F _n of rank n 2 on free generators x ₁, x ₂,...,x _n . It is known that Aut(F ₂) can be built from cyclic subgroups using a free and semidirect product. A question remains open as to whether this result can be extended to the case n > 2. Every automorphism of Aut(F _n ) sending a generator x _i to an element f _i ^-1 x _(i) f _i , where f _i F _n and is some permutation on a symmetric group S _n , is called a conjugating automorphism. The conjugating automorphism group is denoted C _n . A set of automorphisms for which is the identity permutation form a basis-conjugating automorphism group, denoted Cb _n . It is proved that Cb _n can be factored into a semidirect product of some groups. As a consequence we obtain a normal form for words in C _n . For n 4, C _n and Cb _n have an undecidable occurrence problem in finitely generated subgroups. It is also shown that C _n , n 2, is generated by at most four elements, and we find its respective genetic code, and that Cb _n , n 2, has no proper verbal subgroups of finite width.     

The Automorphism Group of a Free-by-Cyclic Group in Rank 2

Let φ be an automorphism of a free group F_n of rank n, and let M_φ = F_n ?_φ ? be the corresponding mapping torus of φ. We study the group Out(M_φ) under certain technical conditions on φ. Moreover, in the case of rank 2, we classify the cases when this group is finite or virtually cyclic, depending on the conjugacy class of the image of φ in GL₂(?). As an application, we solve the isomorphism problem for the family of F₂-by-? groups, in terms of the two defining automorphisms.     

On the Characterizability of the Automorphism Groups of Sporadic Simple Groups by Their Element Orders

For G a finite group, π _e (G) denotes the set of orders of elements in G. If Ω is a subset of the set of natural numbers, h(Ω) stands for the number of isomorphism classes of finite groups with the same set Ω of element orders. We say that G is k-distinguishable if h(π _e (G)) = k < ∞, otherwise G is called non-distinguishable. Usually, a 1-distinguishable group is called a characterizable group. It is shown that if M is a sporadic simple group different from M ₁₂, M ₂₂, J ₂, He, Suz, M ^c L and O′N, then Aut(M) is characterizable by its element orders. It is also proved that if M is isomorphic to M ₁₂, M ₂₂, He, Suz or O′N, then h(π _e (Aut(M))) ∈¸ {1,∞}.