Matrices, Jordan Normal Forms, and Spectral Radius Theory

Matrix interpretations are useful as measure functions in termination proving. In order to use these interpretations also for complexity analysis, the growth rate of matrix powers has to examined. Here, we formalized an important result of spectral radius theory, namely that the growth rate is polynomially bounded if and only if the spectral radius of a matrix is at most one. To formally prove this result we first studied the growth rates of matrices in Jordan normal form, and prove the result that every complex matrix has a Jordan normal form by means of two algorithms: we first convert matrices into similar ones via Schur decomposition, and then apply a second algorithm which converts an upper-triangular matrix into Jordan normal form. We further showed uniqueness of Jordan normal forms which then gives rise to a modular algorithm to compute individual blocks of a Jordan normal form. The whole development is based on a new abstract type for matrices, which is also executable by a ...

• Type: Journal
• Year: 2015
• Where: AFP
• Authors: René Thiemann, Akihisa Yamada 0002
• Keywords: AFP 2015, Formal Methods