Kourovka Notebook Problem 21.51
Let $p$ be a prime, and $P$ a finite $p$-group. (a) Suppose that $P$ has an abelian subgroup of order $p^n$. For which $n$ does $P$ necessarily have ...
Kourovka Notebook Problem 21.52
Let $L$ be a finite non-abelian simple group, and let $D$ be a conjugacy class of involutions in $L$. Consider the complete graph $\Gamma$ with vertex...
Kourovka Notebook Problem 21.53
In the notation of 21.52, let $\operatorname{Aut}_t(\Gamma)$ be the set of permutations $\tau\in S_D$ such that $(a,b)\sim(a^\tau,b^\tau)$ whenever $|...
Kourovka Notebook Problem 21.54
Let $G$ be a finite soluble group with triality, which means that $G$ admits a group of automorphisms $S$ isomorphic to the symmetric group of degree ...
Kourovka Notebook Problem 21.55
Let $q$ be a power of a prime $p$, and let $m_n(q)$ be the maximum $p$-length of $p$-solvable subgroups of $\operatorname{GL}(n,q)$. Is it true that $...
Kourovka Notebook Problem 21.56
Let $\ell(X)$ denote the composition length of a finite group $X$. Let $A$ be a finite nilpotent group acting by automorphisms on a finite soluble gro...
Kourovka Notebook Problem 21.57
Let X be a non-empty class of finite groups of odd order closed under taking subgroups, homomorphic images, and extensions. Let H be an X-maximal subg...
Kourovka Notebook Problem 21.58
We say that a product $XY=\{xy\mid x\in X,\ y\in Y\}$ of two subsets $X,Y$ of a group $G$ is direct if for every $z\in XY$ there are unique $x\in X$, ...
Kourovka Notebook Problem 21.59
For a finite group $G$, let $\chi_1(G)$ denote the totality of the degrees of all irreducible complex characters of $G$ with allowance for their multi...
Kourovka Notebook Problem 21.60
Let $G$ be a finite group, $\mathbb Z_{(p)}$ the localization at $p$, and $\mathbb F_p$ the field of $p$ elements. Let $\mathcal X$ be the class of $\...
Kourovka Notebook Problem 21.61
For a fixed (finitely generated free)-by-cyclic group $G=F_n\rtimes\mathbb Z$, is there an algorithm that, given a finite subset $S$ of $G$, finds a f...
Kourovka Notebook Problem 21.62
Is the uniform subgroup membership problem decidable for (finitely generated free)-by-cyclic groups? That is, for a fixed group $G=F_n\rtimes\mathbb Z...
Kourovka Notebook Problem 21.63
Let $F$ be a field of characteristic $p>0$, and let $\Gamma$ be the principal congruence subgroup of $\operatorname{Aut}(F[x_1,\ldots,x_n])$ consistin...
Kourovka Notebook Problem 21.64
Is it true that if a normal subgroup $A$ of a Sylow $p$-subgroup of a $p$-soluble finite group $G$ has exponent $p^e$, then the normal closure of $A$ ...
Kourovka Notebook Problem 21.65
Suppose that $\phi$ is an automorphism of a finite soluble group $G$. Must $G$ contain a subgroup of index bounded in terms of $|\phi|$ and $|C_G(\phi...
Kourovka Notebook Problem 21.66
Suppose that A is a nilpotent group of automorphisms of a finite soluble group G. Is the Fitting height of G bounded in terms of |A| and |CG(A)|? Isa...
Kourovka Notebook Problem 21.67
Suppose that $\phi$ is an automorphism of a finite soluble group $G$, and let $r$ be the (Pr\"ufer) rank of the fixed-point subgroup $C_G(\phi)$. Is t...
Kourovka Notebook Problem 21.68
A finite group $G$ is said to be semi-abelian if it has a sequence of subgroups $1=G_0\leqslant G_1\leqslant\cdots\leqslant G_n=G$ such that for every...
Kourovka Notebook Problem 21.69
Is there an algorithm deciding if a given one-relator group is hyperbolic?...
Kourovka Notebook Problem 21.70
A group $G$ is called an orientable Poincar\'e duality group of dimension $n$ over a ring $R$ if it is of type $FP$ over $R$ and $H^i(G;RG)=0$ for $i\...
Kourovka Notebook Problem 21.71
For a ring $R$, we say that a group $G$ is of type $FL(R)$ if the trivial $RG$-module $R$ admits a finite resolution by finitely generated free module...
Kourovka Notebook Problem 21.72
We say that a group is a Tarski monster if it is finitely generated, not cyclic, and all of its proper non-trivial subgroups are isomorphic to each ot...
Kourovka Notebook Problem 21.73
Is the conjugacy problem in $\operatorname{CT}(\mathbb Z)$ algorithmically decidable?...
Kourovka Notebook Problem 21.74
Is it algorithmically decidable whether a given element $g\in\operatorname{CT}(\mathbb Z)$ (a) permutes a nontrivial partition of $\mathbb Z$ into re...
Kourovka Notebook Problem 21.75
Given two distinct sets $P_1$ and $P_2$ of odd primes none of which is a subset of the other, is it true that $\langle \operatorname{CT}_{P_1}(\mathbb...
Kourovka Notebook Problem 21.76
Let $\sigma=(\sigma_{ij})$, $1\leqslant i\ne j\leqslant n$, be an irreducible elementary net (carpet) of order $n\geqslant 3$ over a field $K$ (see 19...
Kourovka Notebook Problem 21.77
Let $d$ be an integer that is not divisible by $n$-th powers of primes, let $x^n-d$ be an irreducible polynomial over $\mathbb Q$, let $\theta=\sqrt[n...
Kourovka Notebook Problem 21.78
Let $p$ be a prime and let $G$ be a pro-$p$ group. Suppose that all of the (continuous Galois) cohomology groups $H^n(G,\mathbb F_p)$ of $G$ with coef...
Kourovka Notebook Problem 21.79
Let $G$ be a finitely generated group with a fixed finite generating set $S$ and the corresponding word metric $L_S(*)$. An element $g$ is said to be ...
Kourovka Notebook Problem 21.80
Do there exist finitely generated left-orderable groups with only one nontrivial conjugacy class?...
Kourovka Notebook Problem 21.81
Let $\Gamma$ be a finite simple group and let $N_n(\Gamma)$ denote the set of normal subgroups of the free group $F_n$ of rank $n$ whose quotient is i...
Kourovka Notebook Problem 21.82
Conjecture: For $n\geqslant 3$, there are no finite simple characteristic quotients of the free group $F_n$....
Kourovka Notebook Problem 21.83
Conjecture: Metabelian groups are permutation-stable....
Kourovka Notebook Problem 21.84
For $\sigma\in S_n$ and $\tau\in S_m$, where $n\leqslant m$, let $d_n^{\mathrm{flex}}(\sigma,\tau)=(1/n)\cdot(|\{x\in\{1,\ldots,n\}\mid \sigma(x)\ne\t...
Kourovka Notebook Problem 21.85
Is a flexibly permutation-stable group always permutation-stable?...
Kourovka Notebook Problem 21.86
A group $G$ is said to be sofic if for every finite set $F\subseteq G$ containing $1$ and every $\varepsilon>0$ there exist $n\in\mathbb N$ and a map ...
Kourovka Notebook Problem 21.87
Assume that a finite group G has a family of d-generator subgroups whose indices have no common divisor. Is it true that G can be generated by d+1 ele...
Kourovka Notebook Problem 21.88
Is there a finite non-abelian group $G$ of odd order, with $k(G)$ conjugacy classes, such that $k(G)/|G|=1/17$?...
Kourovka Notebook Problem 21.89
For $n>39$, is it true that the number of conjugacy classes in the symmetric group $S_n$ of degree $n$ is never a divisor of the order of $S_n$? In ot...
Kourovka Notebook Problem 21.90
Let $\Gamma$ be a graph of diameter $d$. For $i\in\{1,2,\ldots,d\}$, let $\Gamma_i$ be the graph on the same vertex set as $\Gamma$ with vertices $u,w...
Kourovka Notebook Problem 21.91
Conjecture: The sum of squares of the degrees of the irreducible $p$-Brauer characters of a finite group $G$ is at least the $p'$-part of $|G|$....
Kourovka Notebook Problem 21.92
Conjecture: The number of irreducible $p$-Brauer characters of a finite group $G$ is bounded above by the maximum of the number of conjugacy classes $...
Kourovka Notebook Problem 21.93
Let $G$ be a group and let $k\geqslant 2$. Let $H_1,\ldots,H_k$ be subgroups of $G$, and $g_1,\ldots,g_k$ elements of $G$ such that the cosets $g_1H_1...
Kourovka Notebook Problem 21.94
The Gruenberg--Kegel graph (or the prime graph) GK(G) of a finite group G is a labelled graph with vertex set consisting of all prime divisors of the ...
Kourovka Notebook Problem 21.95
Is there an almost simple but not simple group which is recognizable by the isomorphism type of its Gruenberg--Kegel graph?...
Kourovka Notebook Problem 21.96
Is it true that a periodic group containing an involution is locally finite if the centralizer of every element of even order is locally finite?...
Kourovka Notebook Problem 21.97
Is it true that for every positive rational number $r$ there exists a finite group $G$ such that $|\operatorname{Aut}(G)|/|G|=r$?...
Kourovka Notebook Problem 21.98
Let w be a multilinear commutator word, and assume that G is a group where the set of w-values is covered by finitely many cyclic subgroups. Is it tru...
Kourovka Notebook Problem 21.99
Conjecture: If $G$ is a transitive permutation group on a finite set $\Omega$, then for any distinct $\alpha,\beta\in\Omega$ there is an element $g\in...
Kourovka Notebook Problem 21.100
Suppose that $A$ and $G$ are finite groups such that $A$ acts coprimely on $G$ by automorphisms. Let $C=C_G(A)$ be the fixed-point subgroup, and let $...