  The Regional Connection Calculus (RCC), developed by computer scientists at the University of Leeds, is based on a primitive C relating regions of space: the intended interpretation of C(x, y) is that the intersection of the closures of the values of x and y is nonempty.  (See  Cohn et al. 1997,  Cohn 1996)  for details and references.) One area of research concerns the definability of shapes in RCC. The extent of what can be defined with this simple primitive is surprising, but the technicalities quickly become complex; see, for instance,  Gotts 1994,  Gotts 1996).  The work cited in  Cohn et al. 1997  describes constraint propagation techniques and encodings in intuitionistic propositional logic as ways of supporting implemented reasoning based on RCC and some of its extensions. More recent work based on RCC addresses representation and reasoning about motion, which of course combines spatial and temporal issues; see  Wolter &amp; Zakharyaschev 2000).  For more information about qualitative theories of movement, with references to other approaches, see  Galton 1997.