L'écriture se simplifie et on obtient accent(X_0;->)=argmin_(accent(X;->))*((frac(1;sigma)*(accent(d;->)-A*accent(X;->))^T*(accent(d;->)-A*accent(X;->))))=argmin_(accent(X;->))*(|*accent(d;->)-A*accent(X;->)*|^2)