lifted domain

lifted domain

   <theory> In {domain theory}, a {domain} with a new {bottom}
   element added.  Given a domain D, the lifted domain, lift D
   contains an element lift d corresponding to each element d in
   D with the same ordering as in D and a new element bottom
   which is less than every other element in lift D.

   In {functional languages}, a lifted domain can be used to
   model a {constructed type}, e.g. the type

   	data LiftedInt = K Int

   contains the values K minint .. K maxint and K bottom,
   corresponding to the values in Int, and a new value bottom.
   This denotes the fact that when computing a value v = (K n)
   the computation of either n or v may fail to terminate
   yielding the values (K bottom) or bottom respectively.

   (In LaTeX, a lifted domain or element is indicated by a
   subscript {\perp}).

   See also {tuple}.