Formal language

About: Formal language is a research topic. Over the lifetime, 5763 publications have been published within this topic receiving 154114 citations.

A Flowchart Language for Quantum Programming

Abstract: Several high-level quantum programming languages have been proposed in the previous research. In this paper, we define a low-level flowchart language for quantum programming, which can be used in implementation of high-level quantum languages and in design of quantum compilers. The formal semantics of the flowchart language is given, and the notion of correctness for programs written in this language is introduced. A structured quantum programming theorem is presented, which provides a technique of translating quantum flowchart programs into programs written in a high-level language, namely, a quantum extension of the while-language.

On the state complexity of intersection of regular languages

Abstract: The following problem has been considered in [3] and [1] : For n regular languages each of which is accepted by an n-state DFA, what is the number of states of a minimum DFA that accepts th e intersection of the n languages in the worst case? Birget in [1] tried to prove that the lower boun d for the above problem is nn . Unfortunately, his proof is incorrect . In the following, we first show what is wrong in Birget's proof, and then we give two proofs for the problem . The first proof i s a modification of Birget's, which shows that nn — n + 1 is a lower bound for the problem . In the second proof, we use a very different approach and show that nn is indeed the lower bound for the problem in the worst case . With the second approach, we are able to show a more general result that given an arbitrary integer k > 0 and k nonnegative integers there exist k regular languages L 1 , . . . , L k such that L 1 is accepted by an n 1 -state DFA, . . ., Lk is accepted by an nk-state DFA and any DFA accepting nl 1 . Denote the set of all binary relations on N by Bn and the set of all total functions on N by Fn . For R1 , R2 E Bn , R I • R 2 denotes the compositio n of R 1 and R2 . Birget uses the following n regular languages in his proof in [1] :

FAdo and GUItar

Abstract: FAdo is an ongoing project which aims to provide a set of tools for symbolic manipulation of formal languages. To allow high-level programming with complex data structures, easy prototyping of algorithms, and portability (to use in computer grid systems for example), are its main features. Our main motivation is the theoretical and experimental research, but we have also in mind the construction of a pedagogical tool for teaching automata theory and formal languages. For the graphical visualization and interactive manipulation a new interface application, GUItar, is being developed. In this paper, we describe the main components of the FAdo system as well as the basics of the graphical interface and editor, the export/import filters and its generic interface with external systems, such as FAdo .

Semantic Service Oriented Architecture

Abstract: This paper describes a new prototype of a semantic Service Oriented Architecture (SOA) called Spec Services. Instead of publishing their API through a protocol like SOAP, as Web Services do, services can register to a service manager a powerful syntactic description or even semantic description of their capabilities. The client entity will then send a syntactic or semantic description of its requirements to the service manager, which will try to find an appropriate formerly registered service and bind them together. Today our service manager can deal with two languages: regular expressions, which is probably the most powerful syntactic-only description language; Prolog, which is only semantic. Nevertheless, this implementation is made, since its beginning, with evolution in mind, i.e. to easily support integration of new additional formal languages.