A subgroup H of a group G is called F-z-supplemented in G if there exists a subgroup K of G, such that G = HK and H∩K≤ Z∞F(G), where Z∞F(G) is the F-hypercenter of G. We obtain some results about the F-z-suppl...A subgroup H of a group G is called F-z-supplemented in G if there exists a subgroup K of G, such that G = HK and H∩K≤ Z∞F(G), where Z∞F(G) is the F-hypercenter of G. We obtain some results about the F-z-supplemented subgroups and use them to determine the structure of some groups.展开更多
Let P be a Sylow p-subgroup of a group G with the smallest generator number d, where p is a prime. Denote by Md(P) = (P1, P2,..., Pd) a set of maximal subgroups of P such that φ(P) = ∩n^d=1Pn. In this paper, w...Let P be a Sylow p-subgroup of a group G with the smallest generator number d, where p is a prime. Denote by Md(P) = (P1, P2,..., Pd) a set of maximal subgroups of P such that φ(P) = ∩n^d=1Pn. In this paper, we investigate the structure of a finite group G under the assumption that the maximal subgroups in Md(P) are weakly s-permutably embedded in G, some interesting results are obtained which generalize some recent results. Finally, we give some further results in terms of weakly s-permutably embedded subgroups.展开更多
Let G be a finite group and N(G)be its norm.Then N(G)is a characteristic subgroup of G which normalizes every subgroup of G.In this paper,we will study the structure of G under one of the following conditions:1)norm q...Let G be a finite group and N(G)be its norm.Then N(G)is a characteristic subgroup of G which normalizes every subgroup of G.In this paper,we will study the structure of G under one of the following conditions:1)norm quotient group G/N(G)is cyclic;2)all Sylow subgroups of G/N(G)are cyclic and in particular if the order of G/N(G)is a square-free number.展开更多
The concept of an abnormal subgroup of a group G is,in a sense,opposite of thatof a normal subgroup of G.In[J.Algebra,28(1974),15-19]Fattahi studied those finitegroups in which each subgroup is either normal or abnorm...The concept of an abnormal subgroup of a group G is,in a sense,opposite of thatof a normal subgroup of G.In[J.Algebra,28(1974),15-19]Fattahi studied those finitegroups in which each subgroup is either normal or abnormal and characterized all suchgroups.In this paper,as a generalization of Fattahi’s result,we study more general groups,i.e.,groups with only s-quasinormal and abnormal subgroups and characterize all suchgroups.Morever,some interesting conclusions are also obtained.展开更多
There is an interesting but difficult problem:Problem When a finite group Gis given,determine a finite group X with Aut(X)=G.The problem was discussed in several articles.Miller[1]determined all X with G=S3,G=S4...There is an interesting but difficult problem:Problem When a finite group Gis given,determine a finite group X with Aut(X)=G.The problem was discussed in several articles.Miller[1]determined all X with G=S3,G=S4and G=Zn,where Snis the symmetric group on n letters and Znis the cyclic group of order n.展开更多
Let G be a hyper finite locally solvable group, A a minimax ZG-medule, a locally defined formation consisting of locally solvable groups, A has no nonzero infinite irreducible ZG-factors, and G ∈ . The following resu...Let G be a hyper finite locally solvable group, A a minimax ZG-medule, a locally defined formation consisting of locally solvable groups, A has no nonzero infinite irreducible ZG-factors, and G ∈ . The following results are proved: if A has a maximal submodule B such that A/B is , central in G and B has no nonzero central ZG-factors, then A has an decomposition; ifA has an irreducible central submodule B such that all ZG-composition factors of A/B are o^eccentric, then A has an decomposition.展开更多
Let G be a finite group.Denote by πe(G) the set of element orders of G,and for any subset m of positive integers denote by h(m)the number of isomorphic classes of G satisfying πe(G)=m.In[1],the authors made th...Let G be a finite group.Denote by πe(G) the set of element orders of G,and for any subset m of positive integers denote by h(m)the number of isomorphic classes of G satisfying πe(G)=m.In[1],the authors made the following conjecture:for all subsets m of positive integers,h(m)∈{0,1,∞}.Recently,Mazurov[2]proved the following result:If m=πe(L3(5)),then h(m)=2.Thus he gave a negative answer to the above conjecture.In this paper,we shall give another example with h(m)=2.展开更多
An element x of a finite group G is said to be real in G if x y=x−1 for some y in G,and quasi-central if xy=x-1 for each y in G.When G is a 2-group,Ω1(G)≤Z(G)and G=Ω2 R(G),we prove that if every real eleme...An element x of a finite group G is said to be real in G if x y=x−1 for some y in G,and quasi-central if xy=x-1 for each y in G.When G is a 2-group,Ω1(G)≤Z(G)and G=Ω2 R(G),we prove that if every real element in G of order 4 is quasi-central in G,then every element c in G of order 4 is real andis normal in G.Further,we show that a group G with a Sylow p-subgroup P is p-nilpotent if and only if N G(P)is p-nilpotent and,for all x in G\N G(P),one of the following holds:(a)every element in P∩Px∩GNp of order p is quasi-central in P,and if p=2,every real element in P∩Px∩GNp of order 4 is quasi-central in P;(b)every element in P∩Px∩GNp of order p is quasi-central in P,and if p=2,[Ω2 R(P∩Px∩GNp),P]⊆Ω1(P∩GNp)∪Z(P∩GNp);(c)|ΩR(P∩Px∩GNp)|≤pp−1.展开更多
For a nontrivial p-group P,a maximal chain of P is a chain of subgroups 1=P0■P1■···■Pn=P with|Pi:Pi−1|=p for i=1,2,...,n,where n is an integer.We determine the structure of finite grou...For a nontrivial p-group P,a maximal chain of P is a chain of subgroups 1=P0■P1■···■Pn=P with|Pi:Pi−1|=p for i=1,2,...,n,where n is an integer.We determine the structure of finite groups having SS-quasinormality of a maximal chain of Sylow subgroups.We obtain new characterizations of finite p-nilpotent groups and supersolvable groups.展开更多
Let G be a finite group.We denote byν(G)the probability that two randomly chosen elements of G generate a nilpotent subgroup.In this paper,we characterize the structure of finite groups G with lower bounds\({1\over p...Let G be a finite group.We denote byν(G)the probability that two randomly chosen elements of G generate a nilpotent subgroup.In this paper,we characterize the structure of finite groups G with lower bounds\({1\over p},\,{{p^{2}+8}\over{9p^{2}}}\)and\({p+3}\over{4p}\)onν(G),where p is a prime divisor of∣G∣.展开更多
Let G be a finite group.A generating set X of G is said to be minimal if no proper subset of X generates G.Let d(G)and m(G)denote the smallest size and the largest size of a minimal generating set of G,respectively.In...Let G be a finite group.A generating set X of G is said to be minimal if no proper subset of X generates G.Let d(G)and m(G)denote the smallest size and the largest size of a minimal generating set of G,respectively.In this paper we present a characterization for finite solvable groups G such that m(G)-d(G)=1 and m(G)≥m(G/N)+m(N)for any non-trivial normal subgroup N of G.展开更多
Let H be a subgroup of a group G. Then H is said to be S-quasinormal in G if HP = PH for every Sylow subgroup P of G; H is said to be S-quasinormally embedded in G if a Sylow p-subgroup of H is also a Sylow p-subgroup...Let H be a subgroup of a group G. Then H is said to be S-quasinormal in G if HP = PH for every Sylow subgroup P of G; H is said to be S-quasinormally embedded in G if a Sylow p-subgroup of H is also a Sylow p-subgroup of some S-quasinormal subgroup of G for each prime p dividing the order of H. In this paper, we say that H is weakly S-embedded in G if G has a normal subgroup T such that HT is an S-quasinormal subgroup of G and H VIT ≤ HSE, where HSE denotes the subgroup of H generated by all those subgroups of H which are S-quasinormally embedded in G. Some results about the influence of weakly S-embedded subgroups on the structure of finite groups are given.展开更多
In this paper, we prove the following theorem: Let p be a prime number, P a Sylow psubgroup of a group G and π = π(G) / {p}. If P is seminormal in G, then the following statements hold: 1) G is a p-soluble gro...In this paper, we prove the following theorem: Let p be a prime number, P a Sylow psubgroup of a group G and π = π(G) / {p}. If P is seminormal in G, then the following statements hold: 1) G is a p-soluble group and P' ≤ Op(G); 2) lp(G) ≤ 2 and lπ(G) ≤ 2; 3) if a π-Hall subgroup of G is q-supersoluble for some q ∈ π, then G is q-supersoluble.展开更多
Let A be a subgroup of a group G and X be a nonempty subset of G. A is said to be X-semipermutable in G if A has a supplement T in G such that A is X-permutable with every subgroup of T. In this paper, we investigate ...Let A be a subgroup of a group G and X be a nonempty subset of G. A is said to be X-semipermutable in G if A has a supplement T in G such that A is X-permutable with every subgroup of T. In this paper, we investigate further the influence of X-semipermutability of some subgroups on the structure of finite groups. Some new criteria for a group G to be supersoluble or p-nilpotent are obtained.展开更多
A graphΓis a Cayley graph on G if and only if AutΓhas a subgroup G acting regularly on VΓ,and a bipartite graphΓis a bi-Cayley graph on a group G if G≤AutΓacts faithfully and regularly on each part ofΓ.In this ...A graphΓis a Cayley graph on G if and only if AutΓhas a subgroup G acting regularly on VΓ,and a bipartite graphΓis a bi-Cayley graph on a group G if G≤AutΓacts faithfully and regularly on each part ofΓ.In this paper,a complete classification is given for the symmetric Cayley graphs or bi-Cayley graphs on a finite simple group of valency ten which admit quasiprimitive or bi-quasiprimitive groups,respectively.展开更多
For a finite group G,the power graph P(G)is a simple connected graph whose vertex set is the set of elements of G and two distinct vertices x and y are adjacent if and only if xi=y or yi=x,for 2≤i,j≤n.In this ...For a finite group G,the power graph P(G)is a simple connected graph whose vertex set is the set of elements of G and two distinct vertices x and y are adjacent if and only if xi=y or yi=x,for 2≤i,j≤n.In this paper,we obtain the distance Laplacian spectrum of power graphs of finite groups such as cyclic groups,dihedral groups,dicyclic groups,abelian groups and elementary abelian p groups.Moreover,we find the largest and second smallest distance Laplacian eigenvalue of power graphs of such groups.展开更多
In this paper, we give some new conditions of the existence of Hall subgroups in non-soluble finite groups, and so the famous Hall theorem and Schur-Zassenhaus theorem are generalized.
A subgroup H of a finite group G is a partial CAP-subgroup of G if there is a chief series of G such that H either covers or avoids every chief factor of the series.The structural impact of the partial cover and avoid...A subgroup H of a finite group G is a partial CAP-subgroup of G if there is a chief series of G such that H either covers or avoids every chief factor of the series.The structural impact of the partial cover and avoidance property of some distinguished subgroups of a group has been studied by many authors.However,there are still some open questions which deserve an answer.The purpose of the present paper is to give a complete answer to one of these questions.展开更多
We first determine in this paper the structure of the generalized Fitting subgroup F* (G) of the finite groups G all of whose defect groups (of blocks) are conjugate under the automorphism group Aut(G) to eithe...We first determine in this paper the structure of the generalized Fitting subgroup F* (G) of the finite groups G all of whose defect groups (of blocks) are conjugate under the automorphism group Aut(G) to either a Sylow p-subgroup or a fixed p-subgroup of G. Then we prove that if a finite group L acts transitively on the set of its proper Sylow p-intersections, then either L/Op(L) has a T.I. Sylow p-subgroup or p = 2 and the normal closure of a Sylow 2-subgroup of L/O2(L) is 2-nilpotent with completely descripted structure. This solves a long-open problem. We also obtain some generalizations of the classic results by Isaacs and Passman on half-transitivity.展开更多
摘要A subgroup H of a group G is called F-z-supplemented in G if there exists a subgroup K of G, such that G = HK and H∩K≤ Z∞F(G), where Z∞F(G) is the F-hypercenter of G. We obtain some results about the F-z-supplemented subgroups and use them to determine the structure of some groups.
基金the National Natural Science Foundation of China(Grant Nos.1120108211171353)+2 种基金China Postdoctoral Science Foundation(Grant No.2013T60866)the Natural Science Foundation of Guangdong Province(Grant No.S201204007267)Outstanding Young Teachers Training Project of Guangdong Province(GrantNo.Yq2013061)
摘要Let P be a Sylow p-subgroup of a group G with the smallest generator number d, where p is a prime. Denote by Md(P) = (P1, P2,..., Pd) a set of maximal subgroups of P such that φ(P) = ∩n^d=1Pn. In this paper, we investigate the structure of a finite group G under the assumption that the maximal subgroups in Md(P) are weakly s-permutably embedded in G, some interesting results are obtained which generalize some recent results. Finally, we give some further results in terms of weakly s-permutably embedded subgroups.
基金Supported by the National Natural Science Foundation of China(Grant No.11661023)the Service Industry Development Guide of Guizhou Province(Grant No.Qian Fa Gai Fu Wu[2018]1181)。
摘要Let G be a finite group and N(G)be its norm.Then N(G)is a characteristic subgroup of G which normalizes every subgroup of G.In this paper,we will study the structure of G under one of the following conditions:1)norm quotient group G/N(G)is cyclic;2)all Sylow subgroups of G/N(G)are cyclic and in particular if the order of G/N(G)is a square-free number.
基金Project supported by Youth Sci Found of Shanxi Province.
摘要The concept of an abnormal subgroup of a group G is,in a sense,opposite of thatof a normal subgroup of G.In[J.Algebra,28(1974),15-19]Fattahi studied those finitegroups in which each subgroup is either normal or abnormal and characterized all suchgroups.In this paper,as a generalization of Fattahi’s result,we study more general groups,i.e.,groups with only s-quasinormal and abnormal subgroups and characterize all suchgroups.Morever,some interesting conclusions are also obtained.
基金Project supported in part by Japan Society for the Promotion of ScienceSupported in part by Grant-in-Aid for Scientific Research(No.8304003,No.08640051),Ministry Education,Science,Soprts and Culture,Japan.
摘要There is an interesting but difficult problem:Problem When a finite group Gis given,determine a finite group X with Aut(X)=G.The problem was discussed in several articles.Miller[1]determined all X with G=S3,G=S4and G=Zn,where Snis the symmetric group on n letters and Znis the cyclic group of order n.
摘要Let G be a hyper finite locally solvable group, A a minimax ZG-medule, a locally defined formation consisting of locally solvable groups, A has no nonzero infinite irreducible ZG-factors, and G ∈ . The following results are proved: if A has a maximal submodule B such that A/B is , central in G and B has no nonzero central ZG-factors, then A has an decomposition; ifA has an irreducible central submodule B such that all ZG-composition factors of A/B are o^eccentric, then A has an decomposition.
摘要Let G be a finite group.Denote by πe(G) the set of element orders of G,and for any subset m of positive integers denote by h(m)the number of isomorphic classes of G satisfying πe(G)=m.In[1],the authors made the following conjecture:for all subsets m of positive integers,h(m)∈{0,1,∞}.Recently,Mazurov[2]proved the following result:If m=πe(L3(5)),then h(m)=2.Thus he gave a negative answer to the above conjecture.In this paper,we shall give another example with h(m)=2.
基金Supported by NSF of China(12061011)NSF of Guangxi(2020GXNSFDA238014,2021GXNSFAA220105)Innovation Project of Guangxi Graduate Education(YCBZ2023021).
摘要An element x of a finite group G is said to be real in G if x y=x−1 for some y in G,and quasi-central if xy=x-1 for each y in G.When G is a 2-group,Ω1(G)≤Z(G)and G=Ω2 R(G),we prove that if every real element in G of order 4 is quasi-central in G,then every element c in G of order 4 is real andis normal in G.Further,we show that a group G with a Sylow p-subgroup P is p-nilpotent if and only if N G(P)is p-nilpotent and,for all x in G\N G(P),one of the following holds:(a)every element in P∩Px∩GNp of order p is quasi-central in P,and if p=2,every real element in P∩Px∩GNp of order 4 is quasi-central in P;(b)every element in P∩Px∩GNp of order p is quasi-central in P,and if p=2,[Ω2 R(P∩Px∩GNp),P]⊆Ω1(P∩GNp)∪Z(P∩GNp);(c)|ΩR(P∩Px∩GNp)|≤pp−1.
基金supported by the National Natural Science Foundation of China(Grant No.11601225)International Science and Technology Cooperation Program of Henan Province(No.262102521044)+2 种基金Foundation for International Cultivation of Henan Advanced Talents(No.GCC2026010)Natural Science Foundation of Henan Province(No.262300420318)Foundation for University Key Teacher by the Ministry of Education of Henan(No.2020GGJS079).
摘要For a nontrivial p-group P,a maximal chain of P is a chain of subgroups 1=P0■P1■···■Pn=P with|Pi:Pi−1|=p for i=1,2,...,n,where n is an integer.We determine the structure of finite groups having SS-quasinormality of a maximal chain of Sylow subgroups.We obtain new characterizations of finite p-nilpotent groups and supersolvable groups.
基金Supported by NSF of China(Grant No.12061011)NSF of Guangxi(Grant Nos.2020GXNSFDA238014,2021GXNSFAA220105)。
摘要Let G be a finite group.We denote byν(G)the probability that two randomly chosen elements of G generate a nilpotent subgroup.In this paper,we characterize the structure of finite groups G with lower bounds\({1\over p},\,{{p^{2}+8}\over{9p^{2}}}\)and\({p+3}\over{4p}\)onν(G),where p is a prime divisor of∣G∣.
基金Supported by China Scholarship Council(Grant No.202208360148)the National Natural Science Foundation of China(Grant Nos.12126415,12261042,12301026)the Natural Science Foundation of Jiangxi Province(Grant No.20232BAB211006).
摘要Let G be a finite group.A generating set X of G is said to be minimal if no proper subset of X generates G.Let d(G)and m(G)denote the smallest size and the largest size of a minimal generating set of G,respectively.In this paper we present a characterization for finite solvable groups G such that m(G)-d(G)=1 and m(G)≥m(G/N)+m(N)for any non-trivial normal subgroup N of G.
基金supported by National Natural Science Foundation of China (Grant Nos.10771172,11001226)Postgraduate Innovation Foundation of Southwest University (Grant Nos. ky2009013,ky2010007)
摘要Let H be a subgroup of a group G. Then H is said to be S-quasinormal in G if HP = PH for every Sylow subgroup P of G; H is said to be S-quasinormally embedded in G if a Sylow p-subgroup of H is also a Sylow p-subgroup of some S-quasinormal subgroup of G for each prime p dividing the order of H. In this paper, we say that H is weakly S-embedded in G if G has a normal subgroup T such that HT is an S-quasinormal subgroup of G and H VIT ≤ HSE, where HSE denotes the subgroup of H generated by all those subgroups of H which are S-quasinormally embedded in G. Some results about the influence of weakly S-embedded subgroups on the structure of finite groups are given.
摘要In this paper, we prove the following theorem: Let p be a prime number, P a Sylow psubgroup of a group G and π = π(G) / {p}. If P is seminormal in G, then the following statements hold: 1) G is a p-soluble group and P' ≤ Op(G); 2) lp(G) ≤ 2 and lπ(G) ≤ 2; 3) if a π-Hall subgroup of G is q-supersoluble for some q ∈ π, then G is q-supersoluble.
基金supported by National Natural Science Foundation of China (Grant Nos. 10771172, 10771180)
摘要Let A be a subgroup of a group G and X be a nonempty subset of G. A is said to be X-semipermutable in G if A has a supplement T in G such that A is X-permutable with every subgroup of T. In this paper, we investigate further the influence of X-semipermutability of some subgroups on the structure of finite groups. Some new criteria for a group G to be supersoluble or p-nilpotent are obtained.
摘要A graphΓis a Cayley graph on G if and only if AutΓhas a subgroup G acting regularly on VΓ,and a bipartite graphΓis a bi-Cayley graph on a group G if G≤AutΓacts faithfully and regularly on each part ofΓ.In this paper,a complete classification is given for the symmetric Cayley graphs or bi-Cayley graphs on a finite simple group of valency ten which admit quasiprimitive or bi-quasiprimitive groups,respectively.
基金Supported by SERB-DST,New Delhi,under the research project number MTR/2017/000084the third author is supported by NSFC (Grant Nos.11931006 and 11971011)。
摘要For a finite group G,the power graph P(G)is a simple connected graph whose vertex set is the set of elements of G and two distinct vertices x and y are adjacent if and only if xi=y or yi=x,for 2≤i,j≤n.In this paper,we obtain the distance Laplacian spectrum of power graphs of finite groups such as cyclic groups,dihedral groups,dicyclic groups,abelian groups and elementary abelian p groups.Moreover,we find the largest and second smallest distance Laplacian eigenvalue of power graphs of such groups.
基金The research is supported by the NNSF of China (Grant 11371335) and the Natural Science Foundation of Shandong Province (Grant ZR2014AL001), China.
摘要In this paper, we give some new conditions of the existence of Hall subgroups in non-soluble finite groups, and so the famous Hall theorem and Schur-Zassenhaus theorem are generalized.
基金supported by MEC of Spain,FEDER of European Union (Grant No.MTM-2007-68010-C03-02)MICINN of Spain (Grant No. MTM-2010-19938-C03-01)+1 种基金National Natural Science Foundation of China (Grant No. 11171353/A010201)Natural Science Fund of Guangdong (Grant No.S2011010004447)
摘要A subgroup H of a finite group G is a partial CAP-subgroup of G if there is a chief series of G such that H either covers or avoids every chief factor of the series.The structural impact of the partial cover and avoidance property of some distinguished subgroups of a group has been studied by many authors.However,there are still some open questions which deserve an answer.The purpose of the present paper is to give a complete answer to one of these questions.
摘要We first determine in this paper the structure of the generalized Fitting subgroup F* (G) of the finite groups G all of whose defect groups (of blocks) are conjugate under the automorphism group Aut(G) to either a Sylow p-subgroup or a fixed p-subgroup of G. Then we prove that if a finite group L acts transitively on the set of its proper Sylow p-intersections, then either L/Op(L) has a T.I. Sylow p-subgroup or p = 2 and the normal closure of a Sylow 2-subgroup of L/O2(L) is 2-nilpotent with completely descripted structure. This solves a long-open problem. We also obtain some generalizations of the classic results by Isaacs and Passman on half-transitivity.