Before revision:  Diffusion models with several assets and a single state variable lead to the classic turnpike , in which optimal portfolios converge under the physical probability , and to the explicit turnpike , which identifies the limit of optimal portfolios in terms of the solution of an ergodic HJB equation.
After revision:  Diffusion models with several assets and a single state variable , the classic turnpike , in which optimal portfolios converge under the physical probability , and to the explicit turnpike , which identifies the limit of optimal portfolios in terms of the solution of an ergodic HJB equation.