# diff(DiffAlgForm) -- exterior differential

## Synopsis

• Usage:
diff w
• Function: diff
• Inputs:
• Outputs:
• an instance of the type DiffAlgForm, the exterior differential of w

## Description

This function computes the exterior differential of a given differential form.

 ```i1 : w = newForm(2,1,2,"a") 2 2 2 2 o1 = (a x + a x x + a x + a x x + a x x + a x )dx + (a x + a x x + 0 0 3 0 1 9 1 6 0 2 12 1 2 15 2 0 1 0 4 0 1 ------------------------------------------------------------------------ 2 2 2 2 a x + a x x + a x x + a x )dx + (a x + a x x + a x + a x x + 10 1 7 0 2 13 1 2 16 2 1 2 0 5 0 1 11 1 8 0 2 ------------------------------------------------------------------------ 2 a x x + a x )dx 14 1 2 17 2 2 o1 : DiffAlgForm``` ```i2 : diff w o2 = ((2a - a )x + (a - 2a )x + (a - a )x )dx dx + ((2a - a )x + (a 1 3 0 4 9 1 7 12 2 0 1 2 6 0 5 ------------------------------------------------------------------------ - a )x + (a - 2a )x )dx dx + ((a - a )x + (2a - a )x + (a - 12 1 8 15 2 0 2 5 7 0 11 13 1 14 ------------------------------------------------------------------------ 2a )x )dx dx 16 2 1 2 o2 : DiffAlgForm```