Many knowledge-intensive processes are driven by business entities about which knowledge workers make decisions and to which they add information. Artifact-centric process models have been proposed to represent such knowledge-intensive processes. Declarative artifact-centric process models use business rules that dene how knowledge experts can make progress in a process. However, in many business situations knowledge experts have to deal with uncertainty and vagueness. Currently, how to deal with such situations cannot be expressed in declarative artifact-centric process models. We propose the use of fuzzy logic to model uncertainty.We use Guard-Stage-Milestone schemas as declarative artifact-centric process notation and we extend them with...