| Institution: | 1. CORE and IAG‐Louvain School of Management, Université catholique de Louvain, Belgium;2. FUNDP‐University of Namur, Belgium, CORE Université catholique de Louvain, Belgium, and IZA, Germany;3. We are grateful to Rabah Amir, Jean J. Gabszewicz, Georg Kirchsteiger, Yann Ménière, Pierre Picard, Thomas Trégou?t, Xavier Wauthy, and two anonymous referees for useful remarks and suggestions on an earlier draft. We also thank seminar participants at Telecom Paris, CESIfo, Core, and FUNDP. Please address correspondence to: Paul Belleflamme, CORE, Université Catholique de Louvain, Voie du Roman Pays, 34 B‐1348 Louvain‐la‐Neuve, Belgium. Phone: +32 10 47 82 91. Fax: +32 10 47 43 01. E‐mail: . |
