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Dessislava H. Kochloukova

Publications and source records attributed to Dessislava H. Kochloukova.

At least 19 recordsLinked to original sources
arXiv2026

On the residual finiteness of the non-abelian exterior square of wreath products and the Grigorchuk group

We show some sufficient conditions ( in terms of properties of $A$, $B$ and $X$) for the non-abelian exterior square $G \wedge G$ to be residually finite, where $G $ is the wreath product $A \wr B$ or the combinatorial wreath product $G = A \wr_X B$, in the latter case $B$ is a free group. We prove that for the Grigorchuk group $G$ the non-abelian exterior square $G \wedge G$ and the non-abelian tensor product $G \otimes G$ are residually finite. We show conditions that imply that $A \wr B$ is not (cohomologically) good in dimension $\leq 2$.

math.GR↗
arXiv2026

On the residual finiteness of the non-abelian exterior square of some Artin groups, constructible soluble groups, generalised Baumslag-Solitar groups and $SL_n(\Z)$

We show that cohomological and homological goodness are equivalent. We prove that if $G$ is a coherent even Artin group or an even Artin group whose underlying graph does not contain 4-clique or a LERF Artin group then $G \otimes G$ and $G \wedge G$ are residually finite. Furthermore for $G$ a RAAG both $G \otimes G$ and $G \wedge G$ are residually $p$-finite for any prime integer $p$. For $G$ a limit group or a Coxeter group we show that $G \wedge G$ is residually finite. For $G$ a soluble group of type $FP_{\infty}$ we prove that the groups $\X(G)$, $ν(G)$, $G \wedge G$ are virtually residually $p$-finite for almost all primes $p$. For $G$ a generalised Baumslag-Solitar group of rank $n \geq 1$ that is residually finite, we show that $G \wedge G$ is residually finite. For $G = SL_n(\Z)$ and $G = GL_n( \mathbb{Z})$, $n \geq 3$, we show that $G \wedge G$ is residually finite.

math.GR↗
arXiv2026

On the residual finiteness of the non-abelian tensor square $G \otimes G$, the non-abelian exterior square $G \wedge G$ and the weak commutativity construction $\X(G)$

We prove that if $G$ is a residually finite group, $\widehat{G}$ is its profinite completion and the map $H_2(G, \mathbb{Z}) $ $ \to H_2(\widehat{G}, \widehat{\mathbb{Z}}),$ induced by the canonical map $G \to \widehat{G}$, is injective, then the non-abelian exterior square $G \wedge G$ is residually finite. We show that if $G$ is a finitely presented centre-by-metabelian group then $ν(G)$, the non-abelian tensor product $G \otimes G$ and the non-abelian tensor square $G \wedge G$ are residually finite. Furthermore we prove that if $G$ be a finitely presented metabelian group then the weak commutative construction $\X(G)$ is residually finite. We discuss a criterion for the $q$-exterior square $G \wedge^q G$ to be residually finite.

math.GR↗
arXiv2026

The free multiplicative Lie algebra $L(P)$ for a finitely generated parafree group $P$

Let $P$ be a group, $L(P)$ be the free multiplicative Lie algebra with normal subgroup $Γ_n(P)$ generated by Lie bracket ``commutators'' of weight $n$ and $\{ γ_n(P) \}$ be the lower central series of $P$. We prove that $Γ_n(P) \simeq γ_n(P)$ for arbitrary $n \geq 1$ and $P$ a finitely generated parafree group such that $H_2(P, \mathbb{Z}) = 0 = H_3(P, \mathbb{Z})$ (e.g. $P$ satisfies the Strong Parafree Conjecture), in particular Ellis's conjecture holds i.e. the above isomorphism holds for finitely generated free group $P$ but this easily implies it holds for any free group.

math.GR↗
arXiv2026

Lie algebras and coherence

We determine some sufficient conditions for the split extension of two free finitely generated non-abelian Lie algebras $L = F_1 \leftthreetimes F_2$ over an infinite field $K$ to be incoherent.

math.RA↗
arXiv2026

Self-similarity of the generalized Baumslag-Solitar groups

We show that all residually finite generalized Baumslag-Solitar groups of rank $n \geq 1$, defined on a finite and connected graph, are self-similar. Furthermore we prove that all residually finite fundamental groups of (finite, connected) graph of groups where all vertex and edge groups are torsion-free and commensurable with the Heisenberg group and all edge groups properly embed in the corresponding vertex groups are self-similar.

math.GR↗
arXiv2026

Hopfian combinatorial wreath products

Let $A$ be an abelian group. We consider sufficient conditions for the combinatorial wreath product $A \wr_X B$ to be Hopfian generalising results of Bradford and Fournier-Facio. For an integer $m \geq 2$ we show an example where $\mathbb{Z}/ \mathbb{Z}_m \wr_X B$ is not Hopfian but $B$ is Hopfian. We describe $Aut(A \wr_X B)$ under some restrictions on $A$, $B$ and $X$.

math.GR↗
arXiv2025

Homological growth of nilpotent-by-abelian pro-p groups

We show that the torsion-free rank of $H_i(M, \mathbb{Z}_p)$ has finite upper bound for $i \leq m$, where $M$ runs through the pro-$p$ subgroups of finite index in a pro-$p$ group $G$ that is (nilpotent of class $c$)-by-abelian such that $ G/N'$ is of type $FP_{2cm}$.

math.GR↗
arXiv2025

HNN extensions of Lie superalgebras

We explicitly describe the structure of HNN extensions of Lie superalgebras. We specify their bases. Moreover, we prove that the HNN extension is a direct sum of two subalgebras: original Lie superalgebra, and the free Lie superalgebra, which free generators are explicitly described. We apply this result to study finite generation of an ideal in a finitely presented Lie superalgebra. As an important tool, we develop Gröbner-Shirshov basis theory for Lie superalgebras by establishing a normal form theorem in terms of admissible bracketings.

math.RA↗
arXiv2024

Finiteness properties of algebraic fibers of group extensions

This survey describes some recent work, by the authors and others, on the existence of algebraic fibrations of group extensions, as well as the finiteness properties of their algebraic fibers, in the realm of both abstract and pro-$p$ groups. We also discuss some applications of these results to (higher) coherence.

math.GR↗
arXiv2023

Homology and cohomology via the partial group algebra

We study partial homology and cohomology from ring theoretic point of view via the partial group algebra $\mathbb{K}_{par}G$. In particular, we link the partial homology and cohomology of a group $G$ with coefficients in an irreducible (resp. indecomposable) $\mathbb{K}_{par}G$-module with the ordinary homology and cohomology groups of $G$ with in general non-trivial coefficients. Furthermore, we compare the standard cohomological dimension $cd_{ \ \mathbb{K}}(G)$ (over a field $\mathbb{K}$) with the partial cohomological dimension $cd_{ \ \mathbb{K}}^{par}(G)$ (over $\mathbb{K}$) and show that $cd_{ \ \mathbb{K}}^{par}(G) \geq cd_{ \ \mathbb{K}}(G)$ and that there is equality for $G = \mathbb{Z}$.

math.GR↗
arXiv2023

On subdirect products of type $FP_n$ of limit groups over Droms RAAGs

We generalize some known results for limit groups over free groups and residually free groups to limit groups over Droms RAAGs and residually Droms RAAGs, respectively. We show that limit groups over Droms RAAGs are free-by-(torsion-free nilpotent). We prove that if $S$ is a full subdirect product of type $FP_s(\mathbb{Q})$ of limit groups over Droms RAAGs with trivial center, then the projection of $S$ to the direct product of any $s$ of the limit groups over Droms RAAGs has finite index. Moreover, we compute the growth of homology groups and the volume gradients for limit groups over Droms RAAGs in any dimension and for finitely presented residually Droms RAAGs of type $FP_m$ in dimensions up to $m$. In particular, this gives the values of the analytic $L^2$-Betti numbers of these groups in the respective dimensions.

math.GR↗
arXiv2023

Weak commutativity, virtually nilpotent groups, and Dehn functions

The group $\mathfrak{X}(G)$ is obtained from $G\ast G$ by forcing each element $g$ in the first free factor to commute with the copy of $g$ in the second free factor. We make significant additions to the list of properties that the functor $\mathfrak{X}$ is known to preserve. We also investigate the geometry and complexity of the word problem for $\mathfrak{X}(G)$. Subtle features of $\mathfrak{X}$ are encoded in a normal abelian subgroup $W<\mathfrak{X}(G)$ that is a module over $\mathbb{Z} Q$, where $Q= H_1(G,\mathbb{Z})$. We establish a structural result for this module and illustrate its utility by proving that $\mathfrak{X}$ preserves virtual nilpotence, the Engel condition, and growth type -- polynomial, exponential, or intermediate. We also use it to establish isoperimetric inequalities for $\mathfrak{X}(G)$ when $G$ lies in a class that includes Thompson's group $F$ and all non-fibered Kähler groups. The word problem is solvable in $\mathfrak{X}(G)$ if and only if it is solvable in $G$. The Dehn function of $\mathfrak{X}(G)$ is bounded below by a cubic polynomial if $G$ maps onto a non-abelian free group.

math.GR↗
arXiv2023

Higher dimensional algebraic fiberings of group extensions

We prove some conditions for the existence of higher dimensional algebraic fibering of group extensions. This leads to various corollaries on incoherence of groups and some geometric examples of algebraic fibers of type $F_n$ but not $FP_{n+1}$ of some groups including pure braid groups and families of poly-surface groups that are fundamental groups of complex projective varieties.

math.GR↗
arXiv2022

Coabelian ideals in $\mathbb{N}$-graded Lie algebras and applications to right angled Artin Lie algebras

We consider homological finiteness properties $FP_n$ of certain $\mathbb{N}$-graded Lie algebras. After proving some general results, see Theorem A, Corollary B and Corollary C, we concentrate on a family that can be considered as the Lie algebra version of the generalized Bestvina-Brady groups associated to a graph $Γ$. We prove that the homological finiteness properties of these Lie algebras can be determined in terms of the graph in the same way as in the group case. In the last version we have corrected some missprints, in particular the statement of Theorem D (from $n-1$-acyclicity to $n-1 - |w|$-acyclicity).

math.GR↗
arXiv2022

Higher dimensional algebraic fiberings for pro-$p$ groups

We prove some conditions for higher dimensional algebraic fibering of pro-$p$ group extensions and we establish corollaries about incoherence of pro-$p$ groups. In particular, if $G = K \rtimes Γ$ is a pro-$p$ group, $Γ$ a finitely generated free pro-$p$ group with $d(Γ) \geq 2$, $K$ a finitely presented pro-$p$ group with $N$ a normal pro-$p$ subgroup of $K$ such that $K/ N \simeq \mathbb{Z}_p$ and $N$ not finitely generated as a pro-$p$ group, then $G$ is incoherent (in the category of pro-$p$ groups). Furthermore we show that if $K$ is a free pro-$p$ group with $d(K) = 2$ then either $Aut_0(K)$ is incoherent (in the category of pro-$p$ groups) or there is a finitely presented pro-$p$ group, without non-procyclic free pro-$p$ subgroups, that has a metabelian pro-$p$ quotient that is not finitely presented i.e. a pro-$p$ version of a result of Bieri-Strebel does not hold.

math.GR↗
arXiv2022

Pro-$p$ completions of $PD_n$-groups

We sharpen earlier work on the pro-$p$ completions of orientable $PD_3$-groups. There are four cases, and we give examples of aspherical 3-manifolds representing each case. In three of the four cases the new results are best possible. We also consider the pro-$p$ completion of some orientable $PD_n$ groups for $n \leq 5$, including surface-by-surface groups.

math.GT↗