Representation Theorems for Positive Solutions of Parabolic Equations
Yehuda Pinchover · Proceedings of the American Mathematical Society · 1988
We determine all the minimal positive solutions of the parabolic equation $Lu = 0$ in ${{\mathbf {R}}^n} \times {{\mathbf {R}}_ - }$, where $L$ has time independent coefficients or $L$ has periodic coefficients in ${x_1}, \ldots ,{x_n}$ and $t$.