The inverse matrix of the variance-matrix is called the "information matrix".

It follows that the entries of the inverse matrix are all integer.

As for covectors, they change by the inverse matrix.

Multiplication with the inverse matrix subtracts the corresponding linear combination from the given row.

It has the unusual property that all elements in its inverse matrix are integers.

Calculate inverse matrix or solve system of linear equations.

Using this notation the inverse matrix is written this way:

Then the inverse matrix of is denoted by .

Alternatively, it can be constructed using 2n variables, with relations describing an ordered pair of mutually inverse matrices.

Then it may be possible to multiply across by the inverse matrix so long as the matrix determinant of is not zero.