Cosmological parameters and the redshift distribution of gravitational lenses.

For known gravitational lens systems the redshift distribution of the lenses is compared with theoretical expectations for 10^4^ Friedmann-Lemaitre cosmological models, which more than cover the range of possible cases. The comparison is used for assigning a relative probability to each of the models. The entire procedure is repeated for different values of the inhomogeneity parameter η and the limiting spectroscopic magnitude m_lim_, which is important for selection effects. The dependence on these two parameters is examined in more detail for the special cases λ_0_=0 and k=0. Previous results that this method is a better probe for λ_0_ than {OMEGA}_0_ are confirmed, but it appears that the low probability of models with large λ_0_ values found using similar methods is due to a selection effect. The power of this method to discriminate between cosmological models can of course be improved if more gravitational lens systems are found. However, our numerical simulations indicate that a reasonable number of observed systems cannot deliver interesting constraints on the cosmological parameters.