Compositional graph models for global computing systems must account for two relevant dimensions, namely structural containment and communication linking. In Milner's bigraphs the two dimensions are made explicit and represented as two loosely coupled structures: the place graph and the link graph. Here, bigraphs are compared with an earlier model, gs-graphs, originally conceived for modelling the syntactical structure of agents with alpha-convertible declarations. We show that gs-graphs are quite convenient also for the new purpose, since the two above entioned dimensions can be recovered by considering only a specific class of hyper-signatures. With respect to bigraphs, gs-graphs can be proved essentially equivalent, with minor differences at the interface level. We argue that gs-graphs offer a simpler and more standard algebraic structure, based on monoidal categories, for representing both states and transitions. Moreover, they can be equipped with a simple type system to check the well-formedness of legal gs-graphs that are shown to characterise binding bigraphs. Another advantage concerns a textual form in terms of sets of assignments, which can make implementation easier in rewriting frameworks like Maude.

On hierarchical graphs: reconciling bigraphs, gs-monoidal theories and gs-graphs

BRUNI, ROBERTO;MONTANARI, UGO GIOVANNI ERASMO;
2014

Abstract

Compositional graph models for global computing systems must account for two relevant dimensions, namely structural containment and communication linking. In Milner's bigraphs the two dimensions are made explicit and represented as two loosely coupled structures: the place graph and the link graph. Here, bigraphs are compared with an earlier model, gs-graphs, originally conceived for modelling the syntactical structure of agents with alpha-convertible declarations. We show that gs-graphs are quite convenient also for the new purpose, since the two above entioned dimensions can be recovered by considering only a specific class of hyper-signatures. With respect to bigraphs, gs-graphs can be proved essentially equivalent, with minor differences at the interface level. We argue that gs-graphs offer a simpler and more standard algebraic structure, based on monoidal categories, for representing both states and transitions. Moreover, they can be equipped with a simple type system to check the well-formedness of legal gs-graphs that are shown to characterise binding bigraphs. Another advantage concerns a textual form in terms of sets of assignments, which can make implementation easier in rewriting frameworks like Maude.
Bruni, Roberto; Montanari, UGO GIOVANNI ERASMO; Plotkin, G.; Terreni, D.
File in questo prodotto:
File Dimensione Formato  
FI-ictcs2012.pdf

accesso aperto

Descrizione: Articolo principale
Tipologia: Documento in Post-print
Licenza: Tutti i diritti riservati (All rights reserved)
Dimensione 789.04 kB
Formato Adobe PDF
789.04 kB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11568/468272
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 14
  • ???jsp.display-item.citation.isi??? 9
social impact