// Test subadditive closure: star(f)
// star(f) = lim_{n->inf} f^{*n} / n
// For affine(r, 0), star returns the same function since it's already subadditive
f := affine(3, 0)
star_f := star(f)
assert( f = star_f )
g := ratency(1, 1) + 1
star_g := star(g)
assert( g >= star_g )
