<
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.