One-Visit Caterpillar Tree Automata

We study caterpillar tree automata [3] that are restricted to enter any subtree at most one time (or k times). We show that, somewhat surprisingly, the deterministic one-visit automata can already, for instance, evaluate trees where the nodes represent some non-associative operations. We show that there exist regular tree languages that cannot be accepted by a one-visit automaton, thus proving a weakened form of a conjecture of Br

• Type: Journal
• Year: 2002
• Where: FUIN
• Authors: Alexander Okhotin, Kai Salomaa, Michael Domaratzki
• Keywords: Caterpillar Tree Automata, Deterministic One-visit Automata, FUIN 2002, Non-associative Operations