On the motivations for Merleau-Ponty’s ontological research

This paper attempts to clarify Merleau-Ponty’s later work by tracing a hitherto overlooked set of concerns that were of key consequence for the formulation of his ontological research. I argue that his ontology can be understood as a response to a set of problems originating in reflections on the intersubjective use of language in dialogue, undertaken in the early 1950s. His study of dialogue disclosed a structure of meaning-formation and pointed towards a theory of truth (both recurring ontological topics) that post-Phenomenology premises could not account for. A study of dialogue shows that speakers’ positions are interchangeable, that speaking subjects are active and passive in varying degrees, and that the intentional roles of subjects and objects are liable to shift or ‘transgress’ themselves. These observations anticipate the concepts of ‘reversibility’ and ‘narcissism’, his later view of activity and passivity, and his later view of intentionality, and sharpened the need to adopt an intersubjective focus in ontological research

Deciding Circular-Arc Graph Isomorphism in Parameterized Logspace

We compute a canonical circular-arc representation for a given circular-arc (CA) graph which implies solving the isomorphism and recognition problem for this class. To accomplish this we split the class of CA graphs into uniform and non-uniform ones and employ a generalized version of the argument given by K\"obler et al (2013) that has been used to show that the subclass of Helly CA graphs can be canonized in logspace. For uniform CA graphs our approach works in logspace and in addition to that Helly CA graphs are a strict subset of uniform CA graphs. Thus our result is a generalization of the canonization result for Helly CA graphs. In the non-uniform case a specific set of ambiguous vertices arises. By choosing the parameter to be the cardinality of this set the obstacle can be solved by brute force. This leads to an O(k + log n) space algorithm to compute a canonical representation for non-uniform and therefore all CA graphs.Comment: 14 pages, 3 figure

Logic Programming for Describing and Solving Planning Problems

A logic programming paradigm which expresses solutions to problems as stable models has recently been promoted as a declarative approach to solving various combinatorial and search problems, including planning problems. In this paradigm, all program rules are considered as constraints and solutions are stable models of the rule set. This is a rather radical departure from the standard paradigm of logic programming. In this paper we revisit abductive logic programming and argue that it allows a programming style which is as declarative as programming based on stable models. However, within abductive logic programming, one has two kinds of rules. On the one hand predicate definitions (which may depend on the abducibles) which are nothing else than standard logic programs (with their non-monotonic semantics when containing with negation); on the other hand rules which constrain the models for the abducibles. In this sense abductive logic programming is a smooth extension of the standard paradigm of logic programming, not a radical departure.Comment: 8 pages, no figures, Eighth International Workshop on Nonmonotonic Reasoning, special track on Representing Actions and Plannin