11,664 research outputs found
A Parameterised Hierarchy of Argumentation Semantics for Extended Logic Programming and its Application to the Well-founded Semantics
Argumentation has proved a useful tool in defining formal semantics for
assumption-based reasoning by viewing a proof as a process in which proponents
and opponents attack each others arguments by undercuts (attack to an
argument's premise) and rebuts (attack to an argument's conclusion). In this
paper, we formulate a variety of notions of attack for extended logic programs
from combinations of undercuts and rebuts and define a general hierarchy of
argumentation semantics parameterised by the notions of attack chosen by
proponent and opponent. We prove the equivalence and subset relationships
between the semantics and examine some essential properties concerning
consistency and the coherence principle, which relates default negation and
explicit negation. Most significantly, we place existing semantics put forward
in the literature in our hierarchy and identify a particular argumentation
semantics for which we prove equivalence to the paraconsistent well-founded
semantics with explicit negation, WFSX. Finally, we present a general proof
theory, based on dialogue trees, and show that it is sound and complete with
respect to the argumentation semantics.Comment: To appear in Theory and Practice of Logic Programmin
Defeasible Logic Programming: An Argumentative Approach
The work reported here introduces Defeasible Logic Programming (DeLP), a
formalism that combines results of Logic Programming and Defeasible
Argumentation. DeLP provides the possibility of representing information in the
form of weak rules in a declarative manner, and a defeasible argumentation
inference mechanism for warranting the entailed conclusions.
In DeLP an argumentation formalism will be used for deciding between
contradictory goals. Queries will be supported by arguments that could be
defeated by other arguments. A query q will succeed when there is an argument A
for q that is warranted, ie, the argument A that supports q is found undefeated
by a warrant procedure that implements a dialectical analysis.
The defeasible argumentation basis of DeLP allows to build applications that
deal with incomplete and contradictory information in dynamic domains. Thus,
the resulting approach is suitable for representing agent's knowledge and for
providing an argumentation based reasoning mechanism to agents.Comment: 43 pages, to appear in the journal "Theory and Practice of Logic
Programming
On Generalized Records and Spatial Conjunction in Role Logic
We have previously introduced role logic as a notation for describing
properties of relational structures in shape analysis, databases and knowledge
bases. A natural fragment of role logic corresponds to two-variable logic with
counting and is therefore decidable. We show how to use role logic to describe
open and closed records, as well the dual of records, inverse records. We
observe that the spatial conjunction operation of separation logic naturally
models record concatenation. Moreover, we show how to eliminate the spatial
conjunction of formulas of quantifier depth one in first-order logic with
counting. As a result, allowing spatial conjunction of formulas of quantifier
depth one preserves the decidability of two-variable logic with counting. This
result applies to two-variable role logic fragment as well. The resulting logic
smoothly integrates type system and predicate calculus notation and can be
viewed as a natural generalization of the notation for constraints arising in
role analysis and similar shape analysis approaches.Comment: 30 pages. A version appears in SAS 200
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