Learning an hypercube

Warm up: Revisiting [NgRe06] Proof

The minima of 4th order momentum momP(V),4 , of an hypercubes P(V) (V orthogonal), over the unit sphere Sn are located at ±v1 ... ±vn , the row vectors of ± V

Proof

Almost there. By orthogonality of V one get singularity.

Calculate 2nd order derivative to obtain minimality.