$$ \begin{eqnarray}\begin{array}{lll} & & {P}_{0}(t,{t}_{1})\\ & & =\left\{\begin{array}{ll}g(t), & 0\notin ({t}_{1},{t}_{1}+\Delta t),\,0\lt t\leqslant {t}_{1},\\ g({t}_{1}), & 0\notin ({t}_{1},{t}_{1}+\Delta t),\,{t}_{1}\lt t\lt {t}_{1}+\Delta t,\\ g(t-\Delta t), & 0\notin ({t}_{1},{t}_{1}+\Delta t),\,{t}_{1}+\Delta t\leqslant t\leqslant 24,\\ 0, & 0\in ({t}_{1},{t}_{1}+\Delta t),\,0\lt t\lt {t}_{1}+\Delta t,\\ g(t-{t}_{1}-\Delta t), & 0\in ({t}_{1},{t}_{1}+\Delta t),\,{t}_{1}+\Delta t\leqslant t\leqslant {t}_{1}+24,\\ g(24-\Delta t), & 0\in ({t}_{1},{t}_{1}+\Delta t),\,{t}_{1}+24\lt t\leqslant 24.\end{array}\right.\end{array}\end{eqnarray}$$ | (17) |