About some symmetries of negation

Reasoning about Frequent Patterns with Negation

Reasoning about Minimal Belief and Negation as

We investigate the problem of reasoning in the propositional fragment of MBNF, the logic of minimal belief and negation as failure introduced by Lifschitz, which can be considered as a unifying framework for several nonmonotonic formalisms, including default logic, autoepistemic logic, circumscription, epistemic queries, and logic programming. We characterize the complexity and provide algorith...

What About Negation in Spatial Reasoning?

How do we reason about spatial descriptions? In recent years a lot of research has been investigated in order to determine factors of complexity in spatial relational reasoning. Several factors like the number of models, the wording of conclusion or relational complexity have been determined. Any of these factors effected reasoning. But the literature focused solemnly on positive premises. Nega...

Double-Negation Elimination in Some Propositional Logics

This article answers two questions (posed in the literature), each concerning the guaranteed existence of proofs free of double negation. A proof is free of double negation if none of its deduced steps contains a term of the form n(n(t)) for some term t, where n denotes negation. The first question asks for conditions on the hypotheses that, if satisfied, guarantee the existence of a double-neg...

Some Issues on Detecting Negation from Text

Negation is present in all human languages and it is used to reverse the polarity of parts of a statement. It is a complex phenomenon that interacts with many other aspects of language. Besides the direct meaning, negated statements often carry a latent positive meaning. Negation can be interpreted in terms of its scope and focus. This paper explores the importance of both scope and focus to ca...