If { u 1 , . . . , u n } {\displaystyle \{u_{1},...,u_{n}\}} are the eigenvalues of an n-dimensional P-matrix, where n > 1 {\displaystyle n>1} , then | arg ⁡ ( u i ) | < π − π n , i = 1 , . . . , n {\displaystyle |\arg(u_{i})|<\pi -{\frac {\pi }{n}},\ i=1,...,n} If { u 1 , . . . , u n } {\displaystyle \{u_{1},...,u_{n}\}} , u i ≠ 0 {\displaystyle u_{i}\neq 0} , i = 1 , . . . , n {\displaystyle i=1,...,n} are the eigenvalues of an n-dimensional P 0 {\displaystyle P_{0}} -matrix, then | arg ⁡ ( u i ) | ≤ π − π n , i = 1 , . . . , n {\displaystyle |\arg(u_{i})|\leq \pi -{\frac {\pi }{n}},\ i=1,...,n}