Jordan canonical form from rational canonical form
When the relevant polynomials split, rational canonical form refines to Jordan form.
Jordan canonical form from rational canonical form: Let be a finite-dimensional vector space over a field , and let be linear. Assume the characteristic polynomial of splits over (for example, is algebraically closed). Then there exists a basis of for which the matrix of is in Jordan canonical form.
This follows by refining the invariant-factor decomposition in rational canonical form from the structure theorem into primary factors, yielding the Jordan canonical form theorem; the Jordan blocks are organized by the roots of the characteristic polynomial.