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Sublinear Ambiguity

机译:Sublinear歧义

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摘要

A context-free grammar G is ambiguous if there is a word that can be generated by G with at least two different derivation trees. Ambiguous grammars are often distinguished by their degree of ambiguity, which is the maximal number of derivation trees for the words generated by them. If there is no such upper bound G is said to be ambiguous of infinite degree. By considering how many derivation trees a word of at most length n may have, we can distinguish context-free grammars with infinite degree of ambiguity by the growth-rate of their ambiguity with respect to the length of the words. It is known that each cycle-free context-free grammar G is either exponentially ambiguous or its ambiguity is bounded by a polynomial. Until now there have only been examples of context-free languages with inherent ambiguity 2{sup}(Θ(n)) and Θ(n{sup}d) for each d∈N{sub}0. In this paper first examples of (linear) context-free languages with nonconstant sublinear ambiguity are presented.
机译:如果有一个包含至少两个不同推导树的G可以生成的单词,则无内容语法G是模糊的。模糊语法通常因其歧义程度而区别,这是由它们产生的单词的最大派生树的最大数量。如果没有这样的上限G,则据说是无限度的暧昧。通过考虑最多长度的单词的衍生树可能具有多少,我们可以通过对词语长度的歧义的生长速度来区分无限程度的歧义。众所周知,每个无循环的无循环语法G是指数模糊的,或者其歧义由多项式限制。到目前为止,只有与每个d∈n{sub} 0的固有歧义2 {sup}(θ(n))和θ(n {sup} d)的无内容歧义的语言的例子。在本文中,提出了第一个(线性)无内容无限性语言的例子,其具有不共同的载体模糊性。

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