This routine is part of the liesymm package and is loaded via with(liesymm) .

It removes forms which are redundant with respect to the generation of the determining equations.

$\mathrm{with}\left(\mathrm{liesymm}\right)\:$

$\mathrm{setup}\left(\right)$

$\mathrm{eq}≔\mathrm{Diff}\left(u\left(x\,t\right)\,x\,t\right)+\mathrm{Diff}\left(u\left(x\,t\right)\,x\right)+{u\left(x\,t\right)}^2=0$

$\mathrm{eq}≔\frac{{\partial }^2}{\partial x\partial t}u\left(x\,t\right)+\frac{\partial }{\partial x}u\left(x\,t\right)+{u\left(x\,t\right)}^2=0$

$\mathrm{forms}≔\mathrm{makeforms}\left(\mathrm{eq}\,u\left(x\,t\right)\,w\right)$

$\mathrm{forms}≔\left[d\left(u\right)-\mathrm{w1}d\left(x\right)-\mathrm{w2}d\left(t\right)\,d\left(\mathrm{w2}\right)\&ˆd\left(t\right)+\left(u^2+\mathrm{w1}\right)d\left(x\right)\&ˆd\left(t\right)\right]$

$\mathrm{forms}≔\mathrm{close}\left(\mathrm{forms}\right)$

$\mathrm{forms}≔\left[d\left(u\right)-\mathrm{w1}d\left(x\right)-\mathrm{w2}d\left(t\right)\,d\left(\mathrm{w2}\right)\&ˆd\left(t\right)+\left(u^2+\mathrm{w1}\right)d\left(x\right)\&ˆd\left(t\right)\,-d\left(\mathrm{w1}\right)\&ˆd\left(x\right)-d\left(\mathrm{w2}\right)\&ˆd\left(t\right)\right]$

$\mathrm{Lrank}\left(\mathrm{forms}\right)$

$\left[d\left(u\right)-\mathrm{w1}d\left(x\right)-\mathrm{w2}d\left(t\right)\,d\left(\mathrm{w2}\right)\&ˆd\left(t\right)+\left(u^2+\mathrm{w1}\right)d\left(x\right)\&ˆd\left(t\right)\right]$