Self-Verifying Pushdown and Queue Automata
We study the computational and descriptional complexity of self-verifying pushdown automata (SVPDA) and self-verifying realtime queue automata (SVRQA). A self-verifying automaton is a nondeterministic device whose nondeterminism is symmetric in the ...
Two-Sided Strictly Locally Testable Languages
A two-sided extension of strictly locally testable languages is presented. In order to determine membership within a two-sided strictly locally testable language, the input must be scanned from both ends simultaneously, whereby it is synchronously checked ...
Decidability Questions for Insertion Systems and Related Models
Insertion systems or insertion grammars are a generative formalism in which words can only be generated by starting with some axioms and by iteratively inserting strings subject to certain contexts of a fixed maximal length. It is known that languages ...
A Complete Taxonomy of Restarting Automata without Auxiliary Symbols*
A complete taxonomy is presented for restarting automata without auxiliary symbols. In this taxonomy, the language classes that are accepted by deterministic and nondeterministic, monotone, weakly monotone, and non-monotone, shrinking and length-reducing ...
Non-Self-Embedding Grammars and Descriptional Complexity
Non-self-embedding grammars are a subclass of context-free grammars which only generate regular languages. The size costs of the conversion of non-self-embedding grammars into equivalent finite automata are studied, by proving optimal bounds for the ...
Generative Capacity of Contextual Grammars with Subregular Selection Languages*
A contextual grammar is a language generating mechanism inspired by generating sentences in natural languages. An existing string can be extended to a new string of the language by adjoining a context before and behind the string or by inserting it into ...
Languages Accepted by Weighted Restarting Automata*
Weighted restarting automata have been introduced to study quantitative aspects of computations of restarting automata. In earlier works we studied the classes of functions and relations that are computed by weighted restarting automata. Here we use them ...