dsubs(deriv=a, expr)

dsubs(deriv1=a, '...', expr)

The first example compares the results of subs and dsubs.

In this case subs returns an expression which contains f', the object being substituted.

Here, dsubs completely removes the f', the left hand side of the substitution equation.

Here is a PDE example.

The dsubs command also works with anticommutative variables, natively, without using the approach explained in PerformOnAnticommutativeSystem.

Set first  and  as suffixes for variables of type/anticommutative (see Setup)

A PDE system example with two unknown anticommutative functions of four variables, two commutative and two anticommutative; to avoid redundant typing in the input that follows and redundant display of information on the screen let's use PDEtools:-diff_table PDEtools:-declare

Now we can enter derivatives directly as the function's name indexed by the differentiation variables and see the display the same way; two PDEs

By inspection, it is clear that the derivatives in pde[2] can be substituted in pde[1] reducing the problem to a simpler one:

Substituting this result for  back into pde[2], then multiplying by  and subtracting from the above also leads to the PDE system solution, that in this case can also be obtained using a different technique passing the whole system directly to pdsolve

DEtools, PDEtools, subs