Isolated master Hadamard conjecture

A square master Hadamard matrix is a master Hadamard matrix of square size, and $F_p$ denotes the Fourier matrix of prime order $p$. A matrix is isolated when it has no nontrivial deformations. Isolated master Hadamard conjecture. The only isolated square master Hadamard matrices are the Fourier matrices $F_p$, with $p$ prime. The source formulates this as an isolation conjecture after computing the defect of master Hadamard matrices; no proof is supplied.