-systems of finite simple groups
Tarski's problem about the elementary theory of free groups has a positive solution.
The Banach-Tarski paradox for the hyperbolic plane (II)
The second author found a gap in the proof of the main theorem in [J. Mycielski, Fund. Math. 132 (1989), 143-149]. Here we fill that gap and add some remarks about the geometry of the hyperbolic plane ℍ².
The categories of free metabelian groups and Lie algebras
The Dehn functions of and
For at least 3, the Dehn functions of and are exponential. Hatcher and Vogtmann proved that they are at most exponential, and the complementary lower bound in the case was established by Bridson and Vogtmann. Handel and Mosher completed the proof by reducing the lower bound for bigger than 3 to the case . In this note we give a shorter, more direct proof of this last reduction.
The geometric invariants of direct products of virtually free groups.
The Grushko decomposition of a finite graph of finite rank free groups: an algorithm.
The irreducible six-dimensional complex representations of that are nontrivial on .
The Johnson homomorphism and the second cohomology of .
The lower central series of the free partially commutative group.
The maximum order of finite groups of outer automorphisms of free groups.
The p-adic Topology on a Free Group: A Counterexample.
The probability that elements of a rank free group generate a rank subgroup.
The ratio and generating function of cogrowth coefficients of finitely generated groups
Let G be a group generated by r elements . Among the reduced words in of length n some, say , represent the identity element of the group G. It has been shown in a combinatorial way that the 2nth root of has a limit, called the cogrowth exponent with respect to the generators . We show by analytic methods that the numbers vary regularly, i.e. the ratio is also convergent. Moreover, we derive new precise information on the domain of holomorphy of γ(z), the generating function associated...
The rhombic dodecahedron and semisimple actions of Aut(Fₙ) on CAT(0) spaces
We consider actions of automorphism groups of free groups by semisimple isometries on complete CAT(0) spaces. If n ≥ 4 then each of the Nielsen generators of Aut(Fₙ) has a fixed point. If n = 3 then either each of the Nielsen generators has a fixed point, or else they are hyperbolic and each Nielsen-generated ℤ⁴ ⊂ Aut(F₃) leaves invariant an isometrically embedded copy of Euclidean 3-space 𝔼³ ↪ X on which it acts as a discrete group of translations with the rhombic dodecahedron as a Dirichlet...
The Symmetries of Classes of Elements in a Free Group of Rank Two.
The Tits alternative for . I: Dynamics of exponentially-growing automorphisms.
The variety of topological groups generated by the free topological group on [0,1]
There are no Phantom Pairs of Mappings to 1-Dimensional CW-Complexes
Two mappings from a CW-complex to a 1-dimensional CW-complex are homotopic if and only if their restrictions to finite subcomplexes are homotopic.
Topology of Finite Graphs.