  ACAC 2009 is organized by the Athens University of Economics and Business
(AUEB) and it is the fourth in a series of meetings that aim to bring together
researchers working on all areas of the theory of algorithms and computational
complexity. These meetings are expected to serve as a lively forum for
presenting results that are in a preliminary stage or have been recently
presented in some major conference. For the first time this year all submitted
papers were reviewed and ACAC also offered to the authors the choice of
publishing their contribution (provided it has not been published anywhere else
before) with the post-proceedings of EPTCS (Electronic Proceedings in
Theoretical Computer Science).
