Horner Systems: How to efficiently evaluate non-commutative polynomials (by matrices)

By viewing non-commutative polynomials, that is, elements in free associative algebras, in terms of linear representations, we generalize Horner’s rule to the non-commutative (multivariate) setting. We introduce the concept of Horner systems (which has parallels to that of companion matrices), discuss their construction and show how they enable the efficient evaluation of non-commutative polynomials by matrices.