Numerical Document Queries Helmut Seidl FB IV – Informatik Universit ¨ at Trier D-54286 Trier, Germany seidl@psi.uni-trier.de Thomas Schwentick Philipps-Universit ¨ at Marburg FB Mathematik und Informatik D-35032 Marburg tick@informatik.uni- marburg.de Anca Muscholl LIAFA, Université Paris 7 2 place Jussieu 75251 Paris, Cedex 05, France anca@liafa.jussieu.fr ABSTRACT 1. INTRODUCTION Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. PODS 2003, June 9-12, 2003, San Diego, CA. Copyright 2003 ACM 1-58113-670-6/03/06 ... 5.00.