Before revision:  We do so by initializing a high-dimensional value function via supervision from a low-dimensional value function  obtained by applying model-based techniques on a low-dimensional problem featuring an approximate system model.
After revision:  We do so by initializing a high-dimensional value function via supervision from a low-dimensional value function . Such a lower-dimensional value function can be obtained by applying model-based techniques on a low-dimensional problem featuring an approximate system model.