The outline of the paper is as follows. In Section 2, we give some
preliminary definitions of terms and define the operations *unfold* and
*fold*. We show how these operations can be used to create canonical
interval relations. In Section 3 we show how *unfold* and *fold*
can also be used to define two operations which maintain the canonicity of
relations in the face of insertions and deletions respectively.
We give algorithms for these update operations.
In Section 4, an examination of the efficiency and limitations of
*unfold* leads us to derive two pairs of successively more optimised
versions of the update operations; the second pair have the added advantage that
they are applicable to arbitrary totally ordered domains. We give algorithms for
the implementation of both pairs of operations.
In Section 5 we give our concluding remarks and directions of current research.