Consider n = 3 above: resultant Ψ Ψ L ( z 1 , z 2 , z 3 , … … , z N ) ∝ ∝ Π Π i < j ( z i − − z j ) 3 is a trial wavefunction; it is not exact, but qualitatively, it reproduces many features of the exact solution and quantitatively, it has very high overlaps with the exact ground state for small systems. Assuming Coulomb repulsion between any two electrons, that ground state Ψ Ψ E D can be determined using exact diagonalisation and the overlaps have been calculated to be close to one. Moreover, with short-range interaction (Haldane pseudopotentials for m > 3 set to zero), Laughlin wavefunction becomes exact, i.e. ⟨ ⟨ Ψ Ψ E D | Ψ Ψ L ⟩ ⟩ = 1 .