max algebra; linear operator; pair of commuting matrices
The max algebra consists of the nonnegative real numbers equipped with two binary operations, maximization and multiplication. We characterize the invertible linear operators that preserve the set of commuting pairs of matrices over a subalgebra of max algebra.
 P. Moller: Theorie algebrique des Systemes a Evenements Discrets. These, Ecole des Mines de Paris, 1988.