  We have studied pseudoscalar correlation functions computed using the overlap
operator. Within the accuracy of our calculation we find that the quark mass
dependence agrees with the prediction of lowest-order Chiral Perturbation
Theory (ChPT) for quark masses in the range of m ~ m_s/2-2m_s. We present the
results of an analysis which assumes lowest-order ChPT to be valid to extract
the low-energy constants Sigma and f_P, as well as the strange quark mass.
Non-perturbative renormalization is implemented via a matching procedure with
data obtained using Wilson fermions in the Schroedinger functional set-up. We
find that the scalar condensate computed here agrees with the one obtained
previously through a finite-size scaling analysis.
