Wilson matrix
Wilson matrix is the following 4 × 4 {\displaystyle 4\times 4} matrix having integers as elements: W = [ 5 7 6 5 7 10 8 7 6 8 10 9 5 7 9 10 ] {\displaystyle W={\begin{bmatrix}5&7&6&5\\7&10&8&7\\6&8&10&9\\5&7&9&10\end{bmatrix}}} This is the coefficient matrix of the following system of linear equations considered in a paper by J. Morris published in 1946: (S1) 5 x + 7 y + 6 z + 5 u = 23 7 x + 10 y + 8 z + 7 u = 32 6 x + 8 y + 10 z + 9 u = 33 5 x + 7 y + 9 z + 10 u = 31 {\displaystyle {\text{(S1)}}\quad {\begin{aligned}5x+7y+6z+5u&=23\\7x+10y+8z+7u&=32\\6x+8y+10z+9u&=33\\5x+7y+9z+10u&=31\end{aligned}}} Morris ascribes the source of the set of equations to one T. S. Wilson but no details about Wilson have been provided. The particular system of equations was used by Morris to illustrate the concept of ill-conditioned system of equations.