On the relationship between fuzzy logic and four-valued relevance logic
  In fuzzy propositional logic, to a proposition a partial truth in [0,1] is
assigned. It is well known that under certain circumstances, fuzzy logic
collapses to classical logic. In this paper, we will show that under dual
conditions, fuzzy logic collapses to four-valued (relevance) logic, where
propositions have truth-value true, false, unknown, or contradiction. As a
consequence, fuzzy entailment may be considered as ``in between'' four-valued
(relevance) entailment and classical entailment.
