We propose a generalisation of Exel’s crossed product by a single endomorphism and a transfer operator to the case of actions of abelian semigroups of endomorphisms and associated transfer operators. The motivating example for our definition yields new crossed products, not obviously covered by familiar theory. Our technical machinery builds on Fowler’s theory of Toeplitz and Cuntz-Pimsner alge...

Given a closed ideal I in a C-algebra A, an ideal J (not necessarily closed) in I, a *-homomorphism α : A → M(I) and a map L : J → A with some properties, based on [3] and [9] we define a C-algebra O(A,α, L) which we call the Crossed Product by a Partial Endomorphism. In the second section we introduce the Crossed Product by a Partial Endomorphism O(X,α, L) induced by a local homeomorphism σ : ...