Title: Cosmological Constraints from a Combined Analysis of the Cluster Mass Function and Microwave Background Anisotropies

Abstract: We present constraints on several cosmological parameters from a combined analysis of the most recent Cosmic Microwave Background anisotropy data and the Sloan Digital Sky Survey cluster mass function. We find that the combination of the two data sets breaks several degeneracies among the parameters and provides the following constraints: $\sigma_8=0.76\pm0.09$, $\Omega_m=0.26^{+0.06}_{-0.07}$, $h=0.66^{+0.05}_{-0.06}$, $n=0.96 \pm 0.05$, $\tau_c=0.07^{+0.07}_{-0.05}$.