Groups and NTS languages
The context-free groups are known to be exactly the finitely generated virtually free groups. We give here a new combinatorial property which characterizes these groups: they are ``locally primary''. A corollary of this property is that the cylinder generated by the group languages is included in the family of NTS languages. In particular, every context- free group language is NTS.
scientific article; zbMATH DE number 4018404
scientific article