By Pavel Surynek. Communicated by Roman Bartak and Tom Schrijvers.
By Yuliya Lierler and Peter Schüller. Communicated by Paul Tarau.
By André Freitas and João C. Pereira da Silva. Communicated by Alessandra Mileo and Thomas Kreenwalner
By Broes De Cat, Bart Bogaerts, and Marc Denecker. Communicated by Marcello Balduccini and Tran Cao Son.
By Ethan K. Jackson, Microsoft Research, Redmond, WA. Communicated by John Gallagher and Michael Leuschel.
By Michael Fink, Vienna University of Technology, Austria
By Håkan Kjellerstrand, Malmoe, Sweden. Communicated by Tom Schrijvers and Roman Bartak
By Fabrizio Riguzzi, Dipartimento di Matematica e Informatica, Univ. of Ferrara, Italy
By Marco Gavanelli
University of Ferrara
By A. Mileo and A. Hogan