Deciding definability in FO2(<h,<v) on trees
نویسندگان
چکیده
منابع مشابه
Deciding definability in FO2(<h, <v) on trees
We prove that it is decidable whether a regular unranked tree language is definable in FO2(<h, <v). By FO2(<h, <v ) we refer to the two variable fragment of first order logic built from the descendant and following sibling predicates. In terms of expressive power it corresponds to a fragment of the navigational core of XPath that contains modalities for going up to some ancestor, down to some d...
متن کاملDeciding Definability by Deterministic Regular Expressions
We investigate the complexity of deciding whether a given regular language can be defined with a deterministic regular expression. Our main technical result shows that the problem is PSPACE-complete if the input language is represented as a regular expression or nondeterministic finite automaton. The problem becomes EXPSPACE-complete if the language is represented as a regular expression with c...
متن کاملCharacterizing and Deciding MSO-Definability of Macro Tree Transductions
A macro tree transduction is MSO definable if and only if it is of linear size increase. Furthermore, it is decidable for a macro tree transduction whether or not it is MSO definable.
متن کاملDeciding the weak definability of Büchi definable tree languages
Weakly definable languages of infinite trees are an expressive subclass of regular tree languages definable in terms of weak monadic second-order logic, or equivalently weak alternating automata. Our main result is that given a Büchi automaton, it is decidable whether the language is weakly definable. We also show that given a parity automaton, it is decidable whether the language is recognizab...
متن کاملDefinability for Downward and Vertical XPath on Data Trees
We study the expressive power of the downward and vertical fragments of XPath equipped with (in)equality tests over data trees. We give necessary and sufficient conditions for a class of pointed data trees to be definable by a set of formulas or by a single formula of each of the studied logics. To do so, we introduce a notion of saturation, and show that over saturated data trees bisimulation ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Logical Methods in Computer Science
سال: 2015
ISSN: 1860-5974
DOI: 10.2168/lmcs-11(3:5)2015