Tropical polyhedra have been recently used to represent disjunctive
invariants in static analysis. To handle larger instances, tropical analogues
of classical linear programming results need to be developed. This motivation
leads us to study a general tropical linear programming problem.
We give an explicit description of the basic solutions of max-linear systems
with two inequalities.
We consider the two-sided eigenproblem Ax= lBx over max algebra. It is shown
that any finite system of real intervals and points can be represented as
spectrum of this eigenproblem.
We study the behavior of max-algebraic powers of a reducible nonnegative n by
n matrix A. We show that for t>3n^2, the powers A^t can be expanded in
max-algebraic powers of the form CS^tR, where C and R are extracted from
columns and rows of certain Kleene stars and S is diadonally similar to a
Boolean matrix. We study the properties of individual terms and show that all
terms, for a given t>3n^2, can be found in O(n^4 log n) operations.
The concept of separation by hyperplanes is fundamental for convex geometry
and its tropical (max-plus) analogue. However, analogous separation results in
max-min convex geometry are based on semispaces. This paper answers the
question which semispaces are hyperplanes and when it is possible to
classically separate by hyperplanes in max-min convex geometry.
We study separation of a closed box from a max-min convex set by max-min
semispace. This can be regarded as an interval extension of known separation
results. We give a constructive proof of the separation in the case when the
box and the max-min convex set satisfy certain condition, and we show that
separation is never possible if this condition does not hold. We also study
separation of max-min convex sets by boxes and by box and semispace.