This volume contains the proceedings of SARA2000, the fourth Symposium on
Abstraction, Reformulations, and Approximation (SARA). The conference was
held at Horseshoe Bay Resort and Conference Club, Lake LBJ, Texas, July 26–
29, 2000, just prior to the AAAI 2000 conference in Austin. Previous SARA
conferences took place at Jackson Hole in Wyoming (1994), Ville d’Est´erel in
Qu´ebec (1995), and Asilomar in California (1998). The symposium grewou t
of a series of workshops on abstraction, approximation, and reformulation that
had taken place alongside AAAI since 1989. This year’s symposium was actually
scheduled to take place at Lago Vista Clubs & Resort on Lake Travis but, due
to the resort’s failure to pay taxes, the conference had to be moved late in the
day. This mischance engendered eleventh-hour reformulations, abstractions, and
resource re-allocations of its own. Such are the perils of organizing a conference.
This is the first SARA for which the proceedings have been published in the
LNAI series of Springer-Verlag.We hope that this is a reflection of the increased
maturity of the field and that the increased visibility brought by the publication
of this volume will help the discipline grow even further.