Solving Not-Substring Constraint with Flat Abstraction

• Not-substring is currently among the least supported types of string constraints, and existing solvers use only relatively crude heuristics. Yet, not-substring occurs relatively often in practical examples and is useful in encoding other types of constraints. In this paper, we propose a systematic way to solve not-substring using based on flat abstraction. In this framework, the domain of string variables is restricted to flat languages and subsequently the whole constraints can be expressed as linear arithmetic formulae. We show that non-substring constraints can be flattened efficiently, and provide experimental evidence that the proposed solution for not-substring is competitive with the state of the art string solvers.

Subject headings

NATURVETENSKAP  -- Data- och informationsvetenskap -- Datavetenskap (hsv//swe)

NATURAL SCIENCES  -- Computer and Information Sciences -- Computer Sciences (hsv//eng)

Keyword

String constraints

Not-substring relation

Flat abstraction

Formal verification

Publication and Content Type

ref (subject category)

kon (subject category)