I rst celebrate the immense success of twentieth century physics, but then urge that the future may bring many surprises, even in the basic structures of physical

Weakly recognizing morphisms from free semigroups onto finite semigroups are a classical way for defining the class of ω-regular languages, i.e., a set of infinite words is weakly recognizable by such a morphism if and only if it is accepted by some Büchi automaton. We consider the descriptional complexity of various constructions for weakly recognizing morphisms. This includes the conversion f...

The communication structure of parallel communicating grammar systems (PCGS) considered as the descriptional complexity of PCGS is investigated here. The aim of the paper is to compare computational power of PCGS’s with respect to their communication structure. Investigating the generation of the languages over one-letter alphabet the communication structures dags(directed acyclic graphs) and c...

We prove that the set of properties describable by a uniform sequence of rst-order sentences using at most k + 1 distinct variables is exactly equal to the set of properties checkable by a Turing machine in DSPACEn k ] (where n is the size of the universe). This set is also equal to the set of properties describable using an iterative deenition for a nite set of relations of arity k. This is a ...

Objective: The aim of this study was to compare the anxiety types school-age children with and without stuttering based on self-report. A further examine possible relationships between levels characteristics in stuttering. Material Methods: participants included 25 who stutter aged 9-12 years (mean age=115.64±9.8 months; 22 boys, 3 girls) age- gender- matched did not age=116.52±10.3 girls). chi...