Where used: Classification Model, State Model

## Tuple

Read First: Relation
A tuple gives a set of things that participate in a relation between
those things. For example, to put Jane and John in the marriage
relation, you create a tuple of Jane and John, (Jane, John) and classify
it by the Marriage relation.
Usually the elements of a tuple are ordered in a certain way to identify
the places, but tuples may be implemented in any manner. The only
requirement is that there is a way to find an element in the tuple given
the place of that element. For example given the tuple expressing the
marriage of Jane and John, there should be a way to find the Jane when
asked for the element filling the Wife place.
We could not think of a case where an object is both a tuple and an
object type, but we also could not prove that one doesn't exist. So we
have left Tuple non-disjoint from Object Type, and consequently,
TupleClassifier non-disjoint from Metaobject Type. Tool that provide an
object that is both and tuple and an object type will need to define a
semantics for the instances of tuple. We would be interested in hearing
about such a semantics.
See comments at Place Relation.

**Hierarchy**:
**Supertypes:** Object
**Subtypes:** None

**Attributes:** None

**Operations:** None