[@Collett15]. Such a significant increase of the number of strong lensing systems will considerably improve the constraints on the cosmological parameters. With a large increase to the known strong lens population, current work could be extended to a new regime: what kind of cosmological results one could obtain from $\sim$10,000 discoverable lens population in the forthcoming Large Synoptic Survey Telescope (LSST) survey?

Using the simulation programs publicly available [^1], we carry out a Monte Carlo simulation of the lens and source populations to forecast the yields of LSST. In our simulation, 10000 SGL systems has been obtain with the proper inputs in the following three assumptions: (i) early-type galaxies act as lenses; (ii) mass distribution of lens is approximated by the power law model; (iii) the normalization and shape of the velocity dispersion function of early-galaxies are not varying with redshift. The assumptions are well consistent with the previous studies on lensing statistics if all galaxies are early-type [@Chae; @Mitchell; @Capelo]. Moreover, we assume a flat concordance $\Lambda$CDM model with $\Omega_m=0.30$ as a fiducial cosmology.

![Scatter plot of 10000 simulated strong lensing systems from future LSST survey.](fig1.eps){width="0.9\linewidth"}

Motivated by several previous studies supporting that early-type galaxies are well described by 