34 ◾ Secure Data Provenance and Inference Control
the domain. DL is characterized by a set of constructors that allow one to build
complex concepts and roles from atomic ones.
L . A DL language
L consists of a countable set of individuals Ind, a
countable set of atomic concepts CS, a countable set of roles RS, and the concepts
built on CS and RS as follows:
C,D: = A|−A|C⊓D|C⊔D|∃R.C|∀R.C|(≤nR.C)|(≥nR.C)
where A∈CS, R∈RS, C, and D are concepts and n is a natural number. Also, indi-
viduals are denoted by a,b,c, . . . (e.g., lowercase letters of the alphabet).
is language includes only concepts in negation normal form. e complement
of a concept −(C) is inductively defined, as usual, by using the law of double nega-
tion, de Morgan laws, a ...