Companion matrix
In linear algebra, the Frobenius companion matrix of the monic polynomial p(t)=c0+c1t+⋯ +cn− 1tn− 1+tn ,{displaystyle p(t)=c_{0}+c_{1}t+cdots +c_{n-1}t^{n-1}+t^{n}~,} is the square matrix defined as C(p)=[00… 0− c010… 0− c101… 0− c2⋮ ⋮ ⋱ ⋮ ⋮ 00… 1− cn− 1].{displaystyle C(p)={begin{bmatrix}0&0&dots &0&-c_{0}\1&0&dots &0&-c_{1}\0&1&dots &0&-c_{2}\vdots &vdots &ddots &vdots &vdots \0&0&dots &1&-c_{n-1}end{bmatrix}}.} With this convention, and on the basis v 1 , ... , v n , one has Cvi=Civ1=vi+1{displaystyle Cv_{i}=C^{i}v_{1}=v_{i+1}} (for i < n ), and v 1 generates V as a K [ C ] -module: C cycles basis vectors. Some authors use the transpose of this matrix, which (dually) cycles coordinates, and is more convenient for some purposes, like linear recurrence relations. Contents 1 Characterization 2 Diagonalizability 3 Linear recursive sequences 4 See also ...