1. discriminated union The discriminated union of two sets A and B is A + B = inA, a | a in A U inB, b| b in B where inA and inB are arbitrary tags which specify which summand an element originates from. A type especially an algebraic data type might be described as a discriminated union if it is a sum type whose objects consist of a tag to say which part of the union they belong to and a value of the corresponding type.
discriminated union |
