This article considers an economy whose production function takes both renewable and non-renewable resources as inputs. We extend the current literature by allowing for exogenous technical change in the elasticity of substitution between these two types of resources. In addition, we study the...

We derive an R&D-based semi-endogenous growth model where technological progress depends on the available amount of technological opportunity. Incremental innovations provide direct increases in the knowledge stock but they reduce technological opportunity and thus the potential for further...