Alternative Characterizations and Relation To Other Formal Languages
As shown by Rajeev Alur and Parthasarathy Madhusudan the class of regular tree languages coincides with nested words and visibly pushdown languages.
The regular tree languages are also the languages recognized by bottom-up tree automata and nondeterministic top-down tree automata.
Regular tree grammars are a generalization of regular word grammars.
Read more about this topic: Regular Tree Grammar
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