The author presents an investigation about presupposition in normative and administrative texts, carried out according to the method of corpus linguistics and Automatic Text Analysis. The cases found were divided into three groups: a) the presupposition is resolved in textual coherence; b) the presupposition is resolved with contextual information and encyclopedic knowledge; c) the presupposition is not resolved. Several examples of each type are cited, discussing the features and possible misunderstandings. In closing the author proposes some practical advises in order to prevent unfair uses of presupposition in public texts.
Keywords: Explicit, implicit, informativeness, misunderstanding, presupposition, rule.