On Finite-Index Indexed Grammars and Their Restrictions
نویسندگان
چکیده
The family, L(INDLIN), of languages generated by linear indexed grammars has been studied in the literature. It is known that the Parikh image of every language in L(INDLIN) is semi-linear. However, there are bounded semi-linear languages that are not in L(INDLIN). Here, we look at larger families of (restricted) indexed languages and study their properties, their relationships, and their decidability properties.
منابع مشابه
Preex Probabilities for Linear Indexed Grammars
We show how preex probabilities can be computed for stochastic linear indexed grammars (SLIGs). Our results apply as well to stochastic tree-adjoining grammars (STAGs), due to their equivalence to SLIGs.
متن کاملSequentially Indexed Grammars
This paper defines the grammar class of sequentially indexed grammars. Sequentially indexed grammars are the result of a change in the index stack handling mechanism of indexed grammars [Aho68, Aho69]. Sequentially indexed grammars are different from linear indexed grammars [Gaz88]. Like indexed languages, sequentially indexed languages are a fully abstract language class. Unlike indexed langua...
متن کاملOn the Computational Complexity of Dominance Links in Grammatical Formalisms
Dominance links were introduced in grammars to model long distance scrambling phenomena, motivating the definition of multiset-valued linear indexed grammars (MLIGs) by Rambow (1994b), and inspiring quite a few recent formalisms. It turns out that MLIGs have since been rediscovered and reused in a variety of contexts, and that the complexity of their emptiness problem has become the key to seve...
متن کاملTowards a Model-Theoretic Characterization of Indexed Grammars
The strong generative capacity of a certain type of indexed grammar is investigated within a model-theoretic framework. Such grammars are found to be equivalent in capacity to a certain fragment of a language obtained by the addition of unary function variables to a monadic second-order language previously used to characterize the context-free grammars.
متن کاملRelating Tabular Parsing Algorithms for Lig and Tag
Tree Adjoining Grammars (TAG) and Linear Indexed Grammars (LIG) are extensions of Context Free Grammars that generate the class of Tree Adjoining Languages. Taking advantage of this property, and providing a method for translating a TAG into a LIG, we define several parsing algorithms for TAG on the basis of their equivalent LIG parsers. We also explore why some practical optimizations for TAG ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2017