Let $F(p)$, $p\ge2$ be the family of generalized Thompson's groups. Here F(2) is the famous Richard Thompson's group usually denoted by $F$. We find the growth rate of the monoid of positive words in $F(p)$ and show that it does not exceed $p+1/2$. Also we describe new normal forms for elements of $F(p)$ and, using these forms, we find a lower bound for the growth rate of $F(p)$ in its natural generators. This lower bound asymptotically equals $(p-1/2)\log_2 e+1/2$ for large values of $p$.
We show that the word problem of the Brin-Higman-Thompson group $n G_{k,1}$ is {\sf coNP}-complete for all $n \ge 2$ and all $k \ge 2$. For this we prove that $n G_{k,1}$ is finitely generated, and that $n G_{k,1}$ contains a subgroup of $2 G_{2,1}$ that can represent bijective circuits. We also show that for all $n \ge 1$ and $k \ge 2$: \ If $\,K = 1 + (k-1)\,N\,$ for some $N \ge 1$, then $n G_{K,1} \le n G_{k,1}$. In particular, $n G_{K,1} \le n G_{2,1}$ for all $K \ge 2$.
The Thompson group $V$, as well as the Brin-Thompson group $2V$, is finitely generated and can be defined as a monoid acting on bitstrings, respectively pairs of bitstrings. Therefore evaluation problems can be defined for $V$ and $2V$. We show that these evaluation problems reduce to the corresponding word problems, and that in general, these evaluation problems are actually equivalent to the word problems. The long-input version of the evaluation problem is deterministic context-free and reverse deterministic context-free for $V,$ and P-complete for $2V$.
We prove that the word problem of the Brin-Thompson group nV over a finite generating set is coNP-complete for every n \ge 2. It is known that the groups nV are an infinite family of infinite, finitely presented, simple groups. We also prove that the word problem of the Thompson group V over a certain infinite set of generators, related to boolean circuits, is coNP-complete.
Groups with Context-Free Co-Word Problem and Embeddings into Thompson's Group $V$
设$G$是一个群生成的群，$Σ$是一个生成$G$为幺半群的有限子集。\emph{word problem of $G$ with respect to $Σ$}由自由幺半群$Σ^{\ast}$中所有与$G$中的恒等式相等的字组成。\emph{co-word problem of $G$ with respect to $Σ$}是字问题在$Σ^{\ast}$中的补充。我们说一个群$G$是\emph{co$\mathcal{CF}$}，如果它关于某个（等价地，任何）有限生成集$Σ$的共字问题是上下文无关语言。我们对每个有限群G描述了一个广义Thompson群$V_{(G, θ)}$和同态$θ$：$G \rightarrow G$ .我们的群体是使用Witzel和Zaremsky介绍的克隆系统构建的。通过构造一个下推自动机，证明了对于任意同态$θ$和有限群G，$V_{(G, θ)}$是coPDMATHABMV，并证明了$V_{(G, θ)}$的co-字问题是我们的自动机所接受的语言的循环移位.一个版本的猜想，由于Lehnert说，一个组有上下文无关的共同字问题正是如果它是一个生成子群的V.组$V_{(G,θ)}$，其中$θ$不是单位同态似乎没有明显的嵌入到V，因此可能被视为反例的猜想。由Bleak和Salazar-Diaz引入的$V$的示范子群可以用来构造某些环积和合并自由积到$V$中的…
本文证明了RichardThompson在20世纪60年代提出的关于无穷单群的新结果。我们定义这些群为部分变换群，并在Cuntz C ~*-代数中给出了一个忠实的表示.对于本文提出的单群T_fin（也称为V），我们证明了字长和表大小满足n log n关系，就像对称群一样.我们证明了T_fin的字问题属于并行复杂性类AC^1（多项式时间的一个子类）。我们证明了T_fin的广义字问题是不可判定的。本文研究了T_fin的畸变函数，证明了T_fin包含所有由线性畸变子群生成的自由群的有限直积.因此，直到函数的多项式等价，以下三个集合是相同的：T_fin的失真集合，所有Dehn函数的集合，以及非确定性图灵机的时间复杂度函数的集合。
We generalize the Brin-Higman-Thompson groups $n G_{k,1}$ to monoids $n M_{k,1}$, for $n \ge 1$ and $k \ge 2$, by replacing bijections by partial functions. The monoid $n M_{k,1}$ has $n G_{k,1}$ as its group of units, and is congruence-simple. Moreover, $n M_{k,1}$ is finitely generated, and for $n \ge 2$ its word problem is {\sf coNP}-complete. We also present new results about higher-dimensional joinless codes.
We show that a large class of languages in the standard finite generating set X = {$x_0, x_1, x_0^{-1}, x_1^{-1}$} cannot be part of an automatic structure for Thompson's Group F. These languages are ones that accept at least one representative of each element of F of word length that is within a fixed constant of a geodesic representative of the element. To accomplish this, we look at a specific element of F and trace two different paths through the Cayley graph to that element. We show that staying within the length restrictions along these two paths would force that element to have contradi…
We give lower bounds on the complexity of the word problem of certain non-solvable groups: for a large class of non-solvable infinite groups, including in particular free groups, Grigorchuk's group and Thompson's groups, we prove that their word problem is $\mathsf{NC}^1$-hard. For some of these groups (including Grigorchuk's group and Thompson's groups) we prove that the compressed word problem (which is equivalent to the circuit evaluation problem) is $\mathsf{PSPACE}$-complete.
We obtain a characterisation of confined subgroups of Thompson's group $F$. As a result, we deduce that orbital graph of a point under action of $F$ has uniformly subexponential growth if and only if this point is fixed by the commutator subgroup. This allows us to prove non-embeddability of $F$ into wobbling groups of graphs with uniformly subexponential growth.
Monoid generalizations of the Richard Thompson groups
Richard Thompson和Graham Higman的群G_{k,1}可以自然地推广到幺半群，我们称之为M_{k,1}，以及逆幺半群，称为Inv_{k,1} ;这可以通过简单地将双射推广到部分函数或部分内射函数来完成。幺半群M_{k,1}与电路复杂性有关（在另一篇论文中研究）。本文证明了M_{k,1}和Inv_{k,1}对所有k都是同余单的.它们的格林关系J和D被刻画为：M_{k,1}和Inv_{k,1}是J-0-单的，并且它们有k-1个非零的D-类.它们是Cuntz代数O_k的乘法部分的子幺半群。它们都是有限生成的，它们在任意有限生成集上的字问题都在P中，它们的字问题在某些无限生成集上是coNP-完全的.本版本的变化：第4节已被彻底修订，错误已被纠正;但是，第4节的主要结果没有变化。除了定理2.3的证明是不完整的外，第1、2和3节没有改变;完整的证明发表在参考文献[6]的附录中，这里也给出了。
The word problem for Thompson's group $F$ has a solution, but it remains unknown whether $F$ is automatic or has a finite or regular convergent (terminating and confluent) rewriting system. We show that the group $F$ admits a natural extension of these two properties, namely autostackability, and we give an explicit bounded regular convergent prefix-rewriting system for $F$.
We describe, through the use of Rubin's theorem, the automorphism groups of the Higman-Thompson groups $G_{n,r}$ as groups of specific homeomorphisms of Cantor spaces $\mathfrak{C}_{n,r}$. This continues a thread of research begun by Brin, and extended later by Brin and Guzmán: to characterise the automorphism groups of the `Chameleon groups of Richard Thompson,' as Brin referred to them in 1996. The work here completes the first stage of that twenty-year-old program, containing (amongst other things) a characterisation of the automorphism group of $V$, which was the `last chameleon.' The home…
Let $1 \le r < n$ be integers. We give a proof that the group $\mathop{\mathrm{Aut}}({X_{n}^{\mathbb{N}}, σ_{n}})$ of automorphisms of the one-sided shift on $n$ letters embeds naturally as a subgroup $\mathcal{H}_{n}$ of the outer automorphism group $\mathop{\mathrm{Out}}({G_{n,r}})$ of the Higman-Thompson group $G_{n,r}$. From this, we can represent the elements of $\mathop{\mathrm{Aut}}({X_{n}^{\mathbb{N}}, σ_{n}})$ by finite state non-initial transducers admitting a very strong synchronizing condition. Let $H \in \mathcal{H}_{n}$ and write $|H|$ for the number of states of the minimal tran…
