A new Rayleigh-Schrödinger pertubation theory (RSPT) sheme along the Pauli (P) contribution is presented, with the unpertubated system being the artificial Kohn-Sham (KS) system of noninteracting fermions, which is linked to the real system of interacting fermions via the Hohenberg-Kohn theorem, with �� = 0, i.e. no Pauli contribution, is scaled up by the coupling strength 0 ≤ �� ≤ 1 to a fictitious system, with �� = 1, i.e. full Pauli contribution, the pertubated system of noninteracting bosons given by the Levy-Perdew-Sahni (LPS) equation. This formalism to introduced in order to give a pathway for constructing novel Kinetic energy density functionals (KEDF) for the Pauli kinetic energy as an (generalized) adiabatic-connection-like (GAC) theorem similar as to for onstructing KS correlation functionals with the adiabatic-connection fluctuation-dissipation (ACFD) theorem or as been done in Görling-Levy pertubation theory (GLPT).