2016/05/19 by Frisch, Sophie · 1 citation
#05A05 #11C08 #13B25 (Primary) #13F20 #15A24 #16A42 #16P10 (Secondary) #FOS: Mathematics #Rings and Algebras (math.RA)
paper · doi:10.48550/arxiv.1605.06027
There are two kinds of polynomial functions on matrix algebras over commutative rings: those induced by polynomials with coefficients in the algebra itself and those induced by polynomials with scalar coefficients. In the case of algebras of upper triangular matrices over a commutative ring, we characterize the former in terms of the latter (which are easier to handle because of substitution homomorphism). We conclude that the set of integer-valued polynomials with matrix coefficients on an algebra of upper triangular matrices is a ring, and that the set of null-polynomials with matrix coefficients on an algebra of upper triangular matrices is an ideal.