Results 31 to 40 of about 252 (156)
Context‐free graphs and their transition groups
Abstract Starting from context‐free inverse graphs, we introduce a new class of groups and study their structural properties. We establish closure properties, show that their coword problems are context‐free, analyze torsion elements, and realize them as subgroups of the asynchronous rational group.
Daniele D'Angeli +3 more
wiley +1 more source
On decomposable pseudofree groups
An Abelian group is pseudofree of rank ℓ if it belongs to the extended genus of ℤℓ, i.e., its localization at every prime p is isomorphic to ℤpℓ.
Dirk Scevenels
doaj +1 more source
Kitaoka's conjecture and sums of squares
Abstract We connect the existence of a ternary classical universal quadratic form over a totally real number field K$K$ with the property that all totally positive multiples of 2 are sums of squares (if K$K$ does not contain 2$\sqrt{2}$ or contains a nonsquare totally positive unit).
Vítězslav Kala +2 more
wiley +1 more source
Groups with minimax commutator subgroup [PDF]
A result of Dixon, Evans and Smith shows that if $G$ is a locally (soluble-by-finite) group whose proper subgroups are (finite rank)-by-abelian, then $G$ itself has this property, i.e. the commutator subgroup of~$G$ has finite rank.
Francesco de Giovanni, Trombetti
doaj
Groups with a finite Busemann boundary are virtually cyclic
Abstract This note is a continuation of the study of the relationship between the geometry of Cayley graphs and the size of its metric‐functional boundary. We show that if there exists a Cayley graph with finitely many Busemann points, then the underlying group is virtually cyclic.
Corentin Bodart +2 more
wiley +1 more source
non-divisibility for abelian groups
Introduction In Throughout all groups are abelian. Suppose that G is a group and n is a positive integer. For a ∈ G, if we consider the solution of the equation nx = a in G, two subsets of G are proposed.
mohammad reza vedadi, yaser Tolooei
doaj
An EZ${\mathcal {E}\mathcal {Z}}$‐structure for the mapping class group
Abstract We construct a boundary for the mapping class group Mod(S)${\rm Mod}(S)$ of a surface S$S$ of finite type. The action of Mod(S)${\rm Mod}(S)$ on this boundary is minimal, strongly proximal and topologically free. The boundary is the boundary of an EZ${\mathcal {E}\mathcal {Z}}$‐structure for Mod(S)${\rm Mod}(S)$.
Ursula Hamenstädt
wiley +1 more source
On automorphism groups of Toeplitz subshifts
On automorphism groups of Toeplitz subshifts, Discrete Analysis 2017:11, 19 pp. A discrete dynamical system is a space $X$ with some kind of structure, together with a map $\sigma\colon X\to X$ that preserves the structure.
Sebastian Donoso +3 more
doaj +1 more source
The Cotypeset of a Torsion Free Abelian Group of Rank Two [PDF]
The cotypeset (set of types of rank one factors) of a torsion free abelian group of rank two is characterized.
Vinsonhaler, C., Wickless, W. J.
openaire +2 more sources
Cohomology of solvable saturable pro‐p$p$ groups and Lie algebras
Abstract Let p$p$ be an odd prime and let n∈N$n\in \mathbb {N}$ be an integer. We show that the n-th$n{\text{-th}}$ mod‐p$p$ cohomology of a solvable saturable pro‐p$p$ group is isomorphic to the n-th$n{\text{-th}}$ mod‐p$p$ cohomology of its associated Zp$\mathbb {Z}_p$‐Lie algebra g$\mathfrak {g}$ as an Fp$\mathbb {F}_p$‐vector space.
Oihana Garaialde Ocaña +2 more
wiley +1 more source

