In this paper we study the properties of systems of bounded arithmetic capturing small complexity classes and state conditions sufficient for such systems to capture the corresponding complexity class tightly. Our class of systems of bounded arithmetic is the class of secondorder systems with comprehension axiom for a syntactically restricted class of formulas Φ ⊂ Σ 1 based on a logic in the de...

We describe our development and use of DescriptiveEnvironment (DE). This is a program to aid researchers in Finite Model Theory and students of logic to automatically generate examples, counterexamples of conjectures, reductions between problems, and visualizations of structures and queries. DescriptiveEnvironment is available for free use under an ISC license at http://www.cs.umass.edu/∼immerm...

We continue with the task of obtaining a unifying view of process semantics by considering in this case the logical characterization of the semantics. We start by considering the classic linear timebranching time spectrum developed by R.J. van Glabbeek. He provided a logical characterization of most of the semantics in his spectrum but, without following a unique pattern. In this paper, we pres...

This paper studies the descriptional complexity of multi-parallel grammars with respect to the number of nonterminals and selectors, and the length of these selectors. As a result, it proves that every recursively enumerable language is generated by a multi-parallel grammar with no more than seven nonterminals and four selectors of length five.

☆ The authors are grateful to Li Qingyang, James Z with data collection, and to Jun Yu and an anonymou the Centre for International Governance Innovation lisches Wilhelms Universität Münster, the June 2011 and Financial Econometrics, the 2011 Western Econo nance Association Conference in Macau — where thi ⁎ Corresponding author at: Wilfrid Laurier Univers E-mail address: [email protected] (P.L. Si...