Departmental Papers (CIS)
Document Type
Book Chapter
Date of this Version
August 2006
Abstract
We study languages of nested trees—structures obtained by augmenting trees with sets of nested jump-edges. These graphs can naturally model branching behaviors of pushdown programs, so that the problem of branching-time software model checking may be phrased as a membership question for such languages. We define finite-state automata accepting such languages—these automata can pass states along jump-edges as well as tree edges. We find that the model-checking problem for these automata on pushdown systems is EXPTIME-complete, and that their alternating versions are expressively equivalent to NT-μ, a recently proposed temporal logic for nested trees that can express a variety of branching-time, "context-free" requirements. We also show that monadic second order logic (MSO) cannot exploit the structure: MSO on nested trees is too strong in the sense that it has an undecidable model checking problem, and seems too weak to capture NT-μ.
Date Posted: 08 December 2006
This document has been peer reviewed.
Comments
Postprint version. Published in Lecture Notes in Computer Science, Volume 4144, Computer Aided Verification, 2006, pages 329-342.
Publisher URL: http://dx.doi.org/10.1007/11817963