Each component in the total regulariser is multiplied with a real scaling factor A I , where I is the component index. To construct and evaluate specific terms in the regulariser, we will adopt a diagrammatic perspective. Since it is beneficial, but not necessary for each component to portray direct physical meaning, we can choose a set of diagrammatic construction rules far less restrictive than e. g. Goldstone, Hugenholtz or Coupled Cluster diagrams. Our chosen ruleset for diagrammatic construction therefore largely adopts the constraints of unitary coupled cluster diagrams with the notable exception that we neglect sign and prefactor of the total diagram. This simplification can be justified by absorbing any generated prefactor into the scaling factor A I . The construction rules for unitary coupled cluster are very similar to those for standard coupled cluster theory with the central distinction that the fermion lines of amplitudes may point in any direction.