  In this paper, we introduce the notion of relation type of analytic and
formal algebras and prove that it is well-defined and invariant by describing
this notion in terms of the Andr\'e-Quillen homology and using the
Jacobi-Zariski long exact sequence of homology. In particular, the relation
type is an invariant of schemes of finite type over a field, analytic
varieties, and algebroid varieties.
