elm in D
in
returns true
if the element elm, which may be an object of any
type, lies in the domain D, and false
otherwise.
gap> 13 in GaussianIntegers; true gap> GaussianIntegers in GaussianIntegers; false gap> (1,2) in D12; false gap> (1,2)(3,6)(4,5) in D12; true
The default function for domain membership tests is DomainOps.'in'
,
which computes the set of elements of the domain with the function
Elements
(see Elements) and tests whether elm lies in this set.
Special domains usually overlay this function with more efficient
membership tests.
GAP 3.4.4