“…The defining properties of algebraic curvature tensors can be used to show (see [4]) that the definition of the kernel of an algebraic curvature tensor is not biased towards the first entry, that is, ker(R) = {y ∈ V | R(x, y, z, w) = 0 for all x, z, w ∈ V } = {z ∈ V | R(x, y, z, w) = 0 for all x, y, w ∈ V } = {w ∈ V | R(x, y, z, w) = 0 for all x, y, z ∈ V }.…”