Fuzzy Categories
  Since categories are graphs with additional "structure", one should start from fuzzy graphs in order to define a theory of fuzzy categories. Thus is makes sense to introduce categories whose morphisms are associated with a plausibility degree that determines to what extend it is possible to "go" from one object to another one. These categories are called {\em fuzzy categories}. Of course, the basic properties of these categories are similar but not identical to their ordinary counterparts. Thus, it is necessary to introduce notion like fuzzy commutative diagrams, fuzzy initial and fuzzy terminal objects, etc. 
Apostolos Syropoulos
cs.LO