2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/107181ODRL is a popular XML-based language for stating the conditions under which resources can be accessed legitimately. The language is described in English and, as a result, agreements written in ODRL are open to interpretation. To address this problem, we propose a formal semantics for a representative fragment of the language. We use this semantics to determine precisely when a permission is implied by a set of ODRL statements and show that answering such questions is a decidable NP-hard problem. Finally, we define a tractable fragment of ODRL that is also fairly expressive.30 pgs, preliminary version presented at WITS-04 (Workshop on Issues in the Theory of Security), 2004Logic in Computer ScienceCryptography and SecurityH.2.7; K.4.4text