Its construction scales as O(O 3 V 2 ) and is therefore allowed. Furthermore, since matrix multiplication scales as O(N 3 ), any power of ρ i j also possesses valid scaling. Even with the restriction of a finite computational scaling prefactor, arbitrary powers of ρ i j can be realised by a transformation to its eigenbasis. By extension, arbitrary analytical functions can be applied to ρ i j via its diagonal representation and will still yield a valid regulariser. Any scheme only possessing finitely many regularisers must therefore arise from an ad hoc truncation of the space of regularisers.