Beyond "yes or no" - Extending access control in groupware with awareness and negotiation

We present three scenarios concerning access to documents in three real wor ld fields of application, which have in common that they are very difficult to support with classical anticipative access control systems. We show, ho w - based on a highly configurable notification and negotiation service, wh ich is tightly integrated with a classical access control system - the comm on permission and denial options can be extended with awareness and negotia tion and how this approach supports the three initial access scenarios. We also introduce our implementation of the notification and negotiation servi ce in the PoliTeam project.