885 research outputs found
Event-driven grammars: Relating abstract and concrete levels of visual languages
The final publication is available at Springer via http://dx.doi.org/10.1007/s10270-007-0051-2In this work we introduce event-driven grammars, a kind of graph grammars that are especially suited for visual modelling environments generated by meta-modelling. Rules in these grammars may be triggered by user actions (such as creating, editing or connecting elements) and in their turn may trigger other user-interface events. Their combination with triple graph transformation systems allows constructing and checking the consistency of the abstract syntax graph while the user is building the concrete syntax model, as well as managing the layout of the concrete syntax representation. As an example of these concepts, we show the definition of a modelling environment for UML sequence diagrams. A discussion is also presented of methodological aspects for the generation of environments for visual languages with multiple views, its connection with triple graph grammars, the formalization of the latter in the double pushout approach and its extension with an inheritance concept.This work has been partially sponsored by the Spanish Ministry of Education and Science with projects MOSAIC (TSI2005-08225-C07-06) and MODUWEB (TIN 2006-09678)
Covering and separation for logical fragments with modular predicates
For every class of word languages, one may associate a decision
problem called -separation. Given two regular languages, it asks
whether there exists a third language in containing the first
language, while being disjoint from the second one. Usually, finding an
algorithm deciding -separation yields a deep insight on
.
We consider classes defined by fragments of first-order logic. Given such a
fragment, one may often build a larger class by adding more predicates to its
signature. In the paper, we investigate the operation of enriching signatures
with modular predicates. Our main theorem is a generic transfer result for this
construction. Informally, we show that when a logical fragment is equipped with
a signature containing the successor predicate, separation for the stronger
logic enriched with modular predicates reduces to separation for the original
logic. This result actually applies to a more general decision problem, called
the covering problem
Efficient and Modular Coalgebraic Partition Refinement
We present a generic partition refinement algorithm that quotients
coalgebraic systems by behavioural equivalence, an important task in system
analysis and verification. Coalgebraic generality allows us to cover not only
classical relational systems but also, e.g. various forms of weighted systems
and furthermore to flexibly combine existing system types. Under assumptions on
the type functor that allow representing its finite coalgebras in terms of
nodes and edges, our algorithm runs in time where
and are the numbers of nodes and edges, respectively. The generic
complexity result and the possibility of combining system types yields a
toolbox for efficient partition refinement algorithms. Instances of our generic
algorithm match the run-time of the best known algorithms for unlabelled
transition systems, Markov chains, deterministic automata (with fixed
alphabets), Segala systems, and for color refinement.Comment: Extended journal version of the conference paper arXiv:1705.08362.
Beside reorganization of the material, the introductory section 3 is entirely
new and the other new section 7 contains new mathematical result
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