Let T:X→ X be a C^1 expanding map, m Gibbs state for a Holder continuous function. Assumef:X→ R^d such that every component fi is a Holder continuous ∫Xfidm=0,i = 1,…,d. If the components of f are cohomologously function with independent then there exists a positive definite symmetric matrix σ^2 such that f^n/√n=f+f.T+…+f.T^n-1/√n converges to in distribution with respect to m to a Gaussian random variable with expectation 0 and covariance matrix σ^2.Moreover,there exists aconstant A 〉 0 such that, for any integer n ≥ 1, we have...