In [BB] Benjamin Baumslag proved that being fully residually free is equivalent to being residually free and commutative transitive (CT). Gaglione and Spellman [GS] and Remeslennikov [Re] showed thatâ€¦ (More)

Let F be a free group of finite rank. We say that the monomorphism problem in F is decidable if there is an algorithm such that, for any two elements u and v in F , it determines whether there existsâ€¦ (More)

In this paper we introduce the geodesic conjugacy language and geodesic conjugacy growth series for a finitely generated group. We study the effects of various group constructions on rationality ofâ€¦ (More)

We say the endomorphism problem is solvable for an element W in a free group F if it can be decided effectively whether, given U in F , there is an endomorphism Ï† of F sending W to U . This workâ€¦ (More)

L systems generalise context-free grammars by incorporating parallel rewriting, and generate languages such as EDT0L and ET0L that are strictly contained in the class of indexed languages. In thisâ€¦ (More)

We consider the cyclic closure of a language, and its gener-alisation to the operators C k introduced by BrandstÃ¤dt. We prove that the cyclic closure of an indexed language is indexed, and that if Lâ€¦ (More)

The study of evaluation and rehabilitation of COPD patient (SERBOC) started in January 2004 in the 6th Medical Clinic of the IaÅŸi Rehabilitation Hospital. One of its goals is to evaluate the leftâ€¦ (More)

We show that, given a word equation over a finitely generated free group, the set of all solutions in reduced words forms an EDT0L language. In particular, it is an indexed language in the sense ofâ€¦ (More)