The paper Iterative Qubit Coupled Cluster approach with efficient screening of generators describes a new screening procedure for generators of the QCC ansatz.
How does one get from defining the flip indices $F(\hat{T})$ of a Pauli term $\hat{P}$:
$$F(\hat{P}) = \{j: \hat{f} ∈\hat{P}\}$$
to the partitioning of the second-quantised Hamiltonian as:
$$\hat{H}=\sum_{k}\hat{S}_{k},$$
where
$$\hat{S}_{k}=\sum_{j}\hat{C}_{j}\hat{P}_{j}$$
groups the terms with the same flip indices?
$$F(\hat{P}_{i})=F(\hat{P}_{j}),\quad ∀(\hat{P}_{i},\hat{P}_{j}) ∈ \hat{S}_{k}$$
And how is it that Pauli words possessing the same flip indices introduce an equivalence relation on the set of Hamiltonian terms?
