ABSTRACT
Relative elliptic theory is an elliptic theory associated with a pair (M,X), where M is a smooth compact manifold and i : X ↪→ M is a smooth compact submanifold. In this chapter, we shall describe a natural class of “operator morphisms” associated with the pair (M,X). This class generalizes the class of pseudodifferential operators (which arises in this context as a special case with X = ∅).
