Decidable Expansions of Labelled Linear Orderings
arXiv:1102.2232 · doi:10.2168/LMCS-7(2:5)2011
Abstract
Consider a linear ordering equipped with a finite sequence of monadic predicates. If the ordering contains an interval of order type ωor -ω, and the monadic second-order theory of the combined structure is decidable, there exists a non-trivial expansion by a further monadic predicate that is still decidable.
18 pages