concept

nature

judge

The inverse is a binomial

judge

use

Each recipe will be one less

Positive inertia is n (n-dimensional quadratic type)

The standard coefficients are all positive numbers (n) or the matrix can be transformed into a diagonal matrix and all elements on the diagonal are >0

Sequential main subexpression>0

The matrix can be reduced to the identity matrix

Elements on the diagonal of the matrix > 0

Matrix corresponding determinant>0

Even order sequence principal formula>0

Odd-order sequential principal formula<0

The corresponding determinant of the matrix is ​​not necessarily <0

Positive inertia is r (r<n), negative inertia is 0

Sequential principal expression ≥ 0

There is no good method, just rely on concepts, it is not difficult to practice