Logic group preprint series 

About: Logic group preprint series is an academic journal. The journal publishes majorly in the area(s): Provability logic & Intuitionistic logic. It has an ISSN identifier of 0929-0710. Over the lifetime, 312 publications have been published receiving 4313 citations.

A computationally efficient approximation of Dempster-Shafer theory

Abstract: An often mentioned obstacle for the use of Dempster-Shafer theory for the handling of uncertainty in expert systems is the computational complexity of the theory. One cause of this complexity is the fact that in Dempster-Shafer theory the evidence is represented by a belief function which is induced by a basic probability assignment, i.e. a probability measure on the powerset of possible answers to a question, and not by a probability measure on the set of possible answers to a question, like in a Bayesian approach. In this paper, we define a Bayesian approximation of a belief function and show that combining the Bayesian approximations of belief functions is computationally less involving than combining the belief functions themselves, while in many practical applications replacing the belief functions by their Bayesian approximations will not essentially affect the result.

Negation and negative concord in romance

Abstract: This paper addresses the two interpretations a combination of negative indefinites can get in concord languages like French, namely a concord reading which amounts to a single negation, or a double negation reading We develop an analysis in a polyadic framework, in which a sequence of negative indefinites can be interpreted as an iteration of quantifiers or as absorption The first option leads to a scopal relation, interpreted as double negation The second option leads to the construction of a polyadic negative quantifier, which corresponds to the concord reading Given that negation participates in negative concord, we develop an extension of the polyadic approach which can deal with non-variable binding operators The contribution of negation in a concord context is semantically empty, which is taken to explain the cross-linguistic variation we find in the participation of negation in negative concord The semantic analysis is incorporated into a grammatical analysis formulated in HPSG, which crucially relies on the assumption that quantifiers can be combined in more than one way upon retrieval from the quantifier store

A logical approach to the dynamics of commitments

Abstract: In this paper we present a formalisation of motivational attitudes, the attitudes that are the driving forces behind the actions of agents. We consider the statics of these attitudes both at the assertion level, i.e. ranging over propositions, and at the practition level, i.e. ranging over actions, as well as the dynamics of these attitudes, i.e. how they change over time. Starting from an agent's wishes, which form the primitive, most funda- mental motivational attitude, we define its goals as induced by those wishes that do not yet hold, i.e. are unfulfilled, but are within the agent's practical possibility to bring about, i.e. are implementable for the agent. Among these unfulfilled, implementable wishes the agent selects those that qualify as its goals. Based on its knowledge on its goals and practical possibilities, an agent may make certain commitments. In particular, an agent may commit itself to actions that it knows to be correct and feasible to bring about some of its known goals. As soon as it no longer knows its commitments to be useful, i.e. leading to fulfilment of some goal, and practically possible, an agent is able to undo these commitments. Both the act of committing as well as that of undoing commitments is modelled as a special model-transforming action in our framework, which extends the usual statetransition paradigm of Propositional Dynamic Logic. In between making and undoing commitments, an agent is committed to all the actions that are known to be identical for all practical purposes to the ones in its agenda. By modifying the agent's agenda during the execution of actions in a straightforward way, it is ensured that commitments display an intuitively acceptable behaviour with regard to composite actions.

Linguistics, Logic, and Finite Trees

Abstract: A modal logic is developed to deal with finite ordered binary trees as they are used in (computational) linguistics. A modal language is introduced with operators for the 'mother of', 'first daughter of' and 'second daughter of' relations together with their transitive reflexive closures. The relevant class of tree models is defined and three linguistic applications of this language are discussed: context free grammars, command relations, and trees decorated with feature structures. An axiomatic proof system is given for which completeness is shown with respect to the class of finite ordered binary trees. A number of decidability results follow.

Proof-Checking a Data Link Protocol

Abstract: A data link protocol developed and used by Philips Electronics is modeled and verified using I/O automata theory. Correctness is computer-checked with the Coq proof development system.