Departmental Papers (CIS)

Date of this Version

August 2006

Document Type

Book Chapter


From the 18th International Conference, CAV 2006, Seattle, WA, USA, August 17-20, 2006.


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.

Subject Area

CPS Theory

Publication Source

Lecture Notes in Computer Science: Computer Aided Verification



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Date Posted: 08 December 2006

This document has been peer reviewed.