The Mortality of a Pair of 2x2 Matrices is Decidable
Résumé
A pair of matrices is said to be mortal if there is a serie of these matrices for which the product is the null matrix. A recent result have established that the general problem of the mortality of a pair of integral matrices is undecidable. In this article, we prove by using only linear algebra that the mortality of a pair of 2x2 integral matrices is decidable.