Simulations of Weighted Tree Automata
نویسندگان
چکیده
Simulations of weighted tree automata (wta) are considered. It is shown how such simulations can be decomposed into simpler functional and dual functional simulations also called forward and backward simulations. In addition, it is shown in several cases (fields, commutative rings, Noetherian semirings, semiring of natural numbers) that all equivalent wta M and N can be joined by a finite chain of simulations. More precisely, in all mentioned cases there is a single wta that simulates both M and N . Those results immediately yield decidability of equivalence provided that the semiring is finitely (and effectively) presented.
منابع مشابه
A Backward and a Forward Simulation for Weighted Tree Automata
Two types of simulations for weighted tree automata (wta) are considered. Wta process trees and assign a weight to each of them. The weights are taken from a semiring. The two types of simulations work for wta over additively idempotent, commutative semirings and can be used to reduce the size of wta while preserving their semantics. Such reductions are an important tool in automata toolkits.
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