Flattening Functions on Flowers

Let T be an orientation-preserving Lipschitz expanding map of the circle T. A pre-image selector is a map τ : T → T with finitely many discontinuities, each of which is a jump discontinuity, and such that τ (x) ∈ T(x) for all x ∈ T. The closure of the image of a pre-image selector is called a flower, and a flower with p connected components is called a p-flower. We say that a real-valued Lipschitz function can be Lipschitz flattened on a flower whenever it is Lipschitz cohomologous to a constant on that flower. The space of Lipschitz functions which can be flattened on a given p-flower is shown to be of codimension p in the space of all Lipschitz functions, and the linear constraints determining this subspace are derived explicitly. If a Lipschitz function f has a maximizing measure S which is Sturmian (i.e. is carried by a 1-flower), it is shown that f can be Lipschitz flattened on some 1-flower carrying S.