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Register a new userOn the Balancedness of Tree-to-word Transducers
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Added by
Raphaela L\\\"obel
Publication date
2019
fields
Informatics Engineering
and research's language is
English
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No Arabic abstract
A language over an alphabet $B = A cup overline{A}$ of opening ($A$) and closing ($overline{A}$) brackets, is balanced if it is a subset of the Dyck language $D_B$ over $B$, and it is well-formed if all words are prefixes of words in $D_B$. We show that well-formedness of a context-free language is decidable in polynomial time, and that the longest common reduced suffix can be computed in polynomial time. With this at a hand we decide for the class 2-TWs of non-linear tree transducers with output alphabet $B^*$ whether or not the output language is balanced.
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We show that equivalence of deterministic linear tree transducers can be decided in polynomial time when their outputs are interpreted over the free group. Due to the cancellation properties offered by the free group, the required constructions are not only more general, but also simpler than the corresponding constructions for proving equivalence of deterministic linear tree-to-word transducers.
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