Matrix polynomial

Matrix polynomial

In mathematics, a matrix polynomial is a polynomial with matrices as variables. Examples include:

P(A) = \sum_{i=0}^n{ a_i A^i} =a_0 I + a_1 A + a_2 A^2 + \cdots + a_n A^n,
where P is a polynomial,
P(x) = \sum_{i=0}^n{ a_i x^i} =a_0  + a_1 x+ a_2 x^2 + \cdots + a_n x^n,
and I is the identity matrix.
\left[A,B\right] = A B - B A,
the commutator of A and B.

A matrix polynomial equation is an equality between two matrix polynomials, which holds for the specific matrices in question. If P(A) = Q(A), (where A is a matrix over a field), then the eigenvalues of A satisfy the characteristic equation[disputed ] P(λ) = Q(λ).
A matrix polynomial identity is a matrix polynomial equation which holds for all matricies A in a specified matrix ring Mn(R).