2015/08/01 by Adam Chapman, Chapman, Adam, Casey Machen +1 · 4 citations
#11R52 #15B33 #FOS: Mathematics #Rings and Algebras (math.RA) #primary 16K20 #secondary 15A18
paper · doi:10.48550/arxiv.1508.00173
Given a central division algebra D of degree d over a field F, we associate to any standard polynomial ϕ(z)=zn+cn-1 zn-1+…+c0 over D a "companion polynomial" Φ(z) of degree n d with coefficients in F whose roots are exactly the conjugacy classes of the roots of ϕ(z). We explain how in case D is a quaternion algebra, all the roots of ϕ(z) can be recovered from the roots of Φ(z). On the way, we also generalize certain theorems that were known for ℍ to any division algebra, such as the connection between the right eigenvalues of a matrix and the roots of its characteristic polynomial, and the connection between the roots of a standard polynomial and left eigenvalues of the companion matrix.