We prove that the relations
in any presentation of the dimension-drop interval are stable, meaning there is a
perturbation of all approximate representations into exact representations. The
dimension-drop interval is the algebra of all Mn-valued continuous function on the
interval that are zero at one end-point and scalar at the other. This has applications
to mod− p K-theory, lifting problems and classification problems in C∗-algebras.
For many applications, the perturbation must respect precise functorial conditions.
To make this possible, we develop a matricial version of Kasparov’s technical
theorem.