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Lecture Notes in Computer Science
It is known that MSO logic for ordered unranked trees is undecidable if Presburger constraints are allowed at children of nodes. We show here that a decidable logic is obtained if we use a modal fixpoint logic instead. We present a characterization of this logic by means of deterministic Presburger tree automata and show how it can be used to express numerical document queries. Surprisingly, the complexity of satisfiability for the extended logic is asymptotically the same as for the originaldoi:10.1007/978-3-540-27836-8_94 fatcat:xa5ds54akbad5h6ex2mtmqm5x4