Parallel composition and unfolding semantics of graph grammars
AUTOR(ES)
Ribeiro, Leila
DATA DE PUBLICAÇÃO
2009
RESUMO
The main aims of this thesis are to provide an approach to the parallel composition of graph grammars and a semantics for graph grammars, called the unfolding semantics, in which the aspects of concurrency and compositionality with respect to the parallel composition play a central role. The parallel composition of graph grammar allows the composition of grammars with respect to a shared part (that may be empty), and is based on parallel and amalgamated composition of the rules of the component grammars. Moreover, the result of the composition is suitably syntactically and semantically related to the component grammars. The unfolding semantics of a graph grammar is a true concurrent, branching structure semantics in which states (graphs) as well as changes of states (derivations) are represented. The unfolding can be constructed incrementally, and we show that this yields the same result as a construction based on gluing of the deterministic computations of a grammar. Moreover, the unfolding of a graph grammar is itself a graph grammar that belong to a special class of graph grammars: the occurrence graph grammars. Here this class is defined axiomatically, and the members of this class can be seen as grammars that represent (deterministic and non-deterministic) computations of another grammars. The semantics of a grammar obtained as the parallel composition of other grammars is isomorphic to the composition of the semantics of the component grammars. As the purpose of the parallel composition is to be a composition for concurrent and reactive systems, the fact that this composition is compatible with a true concurrency semantics is an attractive result.
ASSUNTO(S)
linguagens formais gramatica : grafos
