1.1. Stable propagation. Let M := UT be the open unit cotangent bundle of the n-dimensional Euclidean torus T = R/Z. We express the elements of M in terms of the canonical coordinates (q1, . . . , qn, p1, . . . , pn), where qi ≡ qi + 1. Thus we identify M with T × D, where D = {|p| < 1} is the open unit ball in R and |v| stands for the Euclidean norm of a vector v ∈ R. Consider the space H of a...