Symbolic Register Automata

Abstract

Symbolic Finite Automata and Register Automata are two orthogonal extensions of finite automata motivated by real-world problems where data may have unbounded domains. These automata address a demand for a model over large or infinite alphabets, respectively. Both automata models have interesting applications and have been successful in their own right. In this paper, we introduce Symbolic Register Automata, a new model that combines features from both symbolic and register automata, with a view on applications that were previously out of reach. We study their properties and provide algorithms for emptiness, inclusion and equivalence checking, together with experimental results.

Reasoning About Data Trees Using CHCs

“…They predicate over data words and trees, but they do not support storing, comparing, or combining data from different positions in the model, as that leads quickly to undecidability. Symbolic register automata [10] extend SFAs by storing data values in a set of registers. They retain decidability of the emptiness problem by only allowing equality comparisons between registers and input data.…”

LTL Model Checking for Register Pushdown Systems

“…(Usual) RA with equality and RA with total order can be regarded as NA where the data sets have equality symmetry and total order symmetry, respectively. There are other extensions of RA such as first-order NFA (FO-NFA) [11], RA with linear arithmetic [8] and symbolic RA [12].…”

“…1 , which requires the 2nd register is not changed by the transition and the contents of the 1st and 2nd registers after the transition are not the same. Therefore, one of the possible transitions is (p 0 , 12) where ϕ is uniquely given by the restrictions…”