6 research outputs found
A Modal Logic for Termgraph Rewriting
We propose a modal logic tailored to describe graph transformations and
discuss some of its properties. We focus on a particular class of graphs called
termgraphs. They are first-order terms augmented with sharing and cycles.
Termgraphs allow one to describe classical data-structures (possibly with
pointers) such as doubly-linked lists, circular lists etc. We show how the
proposed logic can faithfully describe (i) termgraphs as well as (ii) the
application of a termgraph rewrite rule (i.e. matching and replacement) and
(iii) the computation of normal forms with respect to a given rewrite system.
We also show how the proposed logic, which is more expressive than
propositional dynamic logic, can be used to specify shapes of classical
data-structures (e.g. binary trees, circular lists etc.)
Informational representability: Abstract models versus concrete models.
International audienc
Spatial logics with connectedness predicates
We consider quantifier-free spatial logics, designed for qualitative spatial representation and reasoning in AI, and extend them with the means to represent topological connectedness of regions and restrict the number of their connected components. We investigate the computational complexity of these logics and show that the connectedness constraints can increase complexity from NP to PSpace, ExpTime and, if component counting is allowed, to NExpTime