
doi: 10.1007/bf01442207
Let us consider a solution of the parabolic PDE \[ \partial g/\partial t=\Delta g+b(x)\nabla g,\quad t>0,\quad g(x,0)=g^ 0(x)>0. \] Under suitable hypotheses it is known [\textit{W. H. Fleming}, Appl. Math. Optimization 4, 329-346 (1978; Zbl 0398.93068)] that \(I(T,x)=-\log g(T,x)\) is the optimal cost of the stochastic control problem: \[ \min imize\quad I(T,x;u)=Ex\{\int^{T}_{0}| b(\xi_ t)-u_ t|^ 2dt-\log g^ 0(\xi_ t)\} \] where \(d\xi_ t=u_ tdt+dW_ t\), \(\xi_ 0=x\). Under the condition that \(b\in C_ b^{\infty}\) the same variational representation is given for the fundamental solution p(t,x,y) that is when \(g^ 0(x)=\delta (x-y)\). In this case, however, the limiting form of the above control problem has \(I\equiv +\infty\) because the endpoint is fixed at y. To overcome this difficulty, for each \(\alpha >0\), the cost is computed up to time T-\(\alpha\) with a suitable penalty function \(F_{\alpha}(\xi_{T-\alpha})\). Then by letting \(\alpha\) \(\to 0\) a new cost function is obtained whose minimum value is shown to be \(I(T,x,y)=-\log p(t,x,y)\). The optimal control is computed in the standard dynamic programming way from I. The proof is a nice application of a result of Molchanov about the asymptotic behavior of p(t,x,y) for small t. The same strategy is then applied to solve a stochastic control problem with a more general loss function L (but with less than quadratic growth) with fixed endpoints.
dynamic programming, Asymptotic behavior of solutions to PDEs, Dynamic programming in optimal control and differential games, Fundamental solutions to PDEs, Existence of optimal solutions to problems involving randomness, Optimal stochastic control, logarithmic transformation, diffusions with, stochastic control, Initial value problems for second-order parabolic equations, Diffusion processes, fundamental solutions, fixed endpoints
dynamic programming, Asymptotic behavior of solutions to PDEs, Dynamic programming in optimal control and differential games, Fundamental solutions to PDEs, Existence of optimal solutions to problems involving randomness, Optimal stochastic control, logarithmic transformation, diffusions with, stochastic control, Initial value problems for second-order parabolic equations, Diffusion processes, fundamental solutions, fixed endpoints
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 21 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Top 10% | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Top 10% | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Average |
