Perceptual Features

a* (b + c) = a*b + a* c

On the left hand side there is a form (a + b)
Expressed in the CMS as: HAS-FORM-[+_A_B]

See Features in the CMS

Features are patterns of mathematical expressions.
For example consider the proposition that a* (b + c) = a*b + a* c
On the left hand side there is the term
(b + c).
This is a form a + b where we have used a canonical representation of the letters.
This feature is expressed in the CMS as HAS-FORM-[+_A_B].
For more details on features see features in the CMS.