原始函数

变换函数

$q\left(x,t\right)=\frac{\partial u\left(x,t\right)}{\partial x}$

$\tilde{q}\left(k_{x,}{k}_t\right)=\left(k_x+1\right)\tilde{u}\left(k_x+1,k_t\right)$

$q\left(x,t\right)=\frac{\partial u\left(x,t\right)}{\partial t}$

$\tilde{q}\left(k_{x,}{k}_t\right)=\left(k_t+1\right)\tilde{u}\left(k_x,k_t+1\right)$

$q\left(x,t\right)=u\left(x,t\right)v\left(x,t\right)$

$\tilde{q}\left(k_x,k_t\right)={\displaystyle \sum _{r=0}^{k_x}{\displaystyle \sum _{s=0}^{k_t}\tilde{u}\left(k_x,k_t\right)\tilde{v}\left(k_x-r,k_t-s\right)}}$