“…Proposition 5.1) which play a pivotal rôle in the algebraic approach to linear quantum field theory, see e.g. [22,45] for textbooks, [8,9,17,43,48] for recent reviews, [18][19][20][21] for homotopical approaches and [23][24][25][30][31][32][33][34][35][36] for some applications. However, differently from [46,47], the Green operator will not have the usual support property due to the non-local behavior of the APS boundary condition.…”