1 research outputs found
Chain-Free String Constraints (Technical Report)
We address the satisfiability problem for string constraints that combine
relational constraints represented by transducers, word equations, and string
length constraints. This problem is undecidable in general. Therefore, we
propose a new decidable fragment of string constraints, called weakly chaining
string constraints, for which we show that the satisfiability problem is
decidable. This fragment pushes the borders of decidability of string
constraints by generalising the existing straight-line as well as the acyclic
fragment of the string logic. We have developed a prototype implementation of
our new decision procedure, and integrated it into in an existing framework
that uses CEGAR with under-approximation of string constraints based on
flattening. Our experimental results show the competitiveness and accuracy of
the new framework