Cosmological constraints from lensing statistics and supernovae on the cosmic equation of state

We investigate observational constraints from lensing statistics and high-$z$ type Ia supernovae on flat cosmological models with nonrelativistic matter and an exotic fluid with an equation of state, $p_x=(m/3\mathrm{}-1){\rho }_x.$ We show that agreement with both tests at the 68% confidence level is possible if the parameter m is low $(m\lesssim 0.85)$ and $0.24\lesssim {\Omega }_{m0\mathrm{}}\lesssim 0.38$ with lower values of ${\Omega }_{m0\mathrm{}}$ corresponding to higher m. We find that a conventional cosmological constant model with ${\Omega }_{m0\mathrm{}}\simeq 0.33$ is the best fit model of the combined likelihood.