We show that one can approximate the least fixed point solution for a
multivariate system of monotone probabilistic max(min) polynomial equations,
referred to as maxPPSs (and minPPSs, respectively), in time polynomial in both
the encoding size of the system of equations and in log(1/epsilon), where
epsilon > 0 is the desired additive error bound of the solution.
We study the computational complexity of central analysis problems for
One-Counter Markov Decision Processes (OC-MDPs), a class of finitely-presented,
countable-state MDPs. OC-MDPs are equivalent to a controlled extension of
(discrete-time) Quasi-Birth-Death processes (QBDs), a stochastic model studied
heavily in queueing theory and applied probability. They can thus be viewed as
a natural ``adversarial'' version of a classic stochastic model. Alternatively,
they can also be viewed as a natural probabilistic/controlled extension of
classic one-counter automata.