how to prevent decomposition



>> I'm stuck about one "simple" problem
>> I have to keep the "b^2-1" from decomposition to
>> "(b-1)*(b+1)" and don't  know how to reach this. Is there a
>> way to keep the form like
>> "b^2-1"  or (b+1)^2  from expansion?
>
>I don't understand the question.  Maxima will only factor (b^2-1) into
>(b-1)*(b+1) if you explicitly call 'factor'.  Could you give some more
>context for the question, and perhaps an example?
Sorry for the english. 
"factor" is one of the main tool for simplification. In my program I use
functions "factorsum" and "factorfacsum"   from facexp package.
These functions gives the final result in acceptable form exept that 
they factors forms like b^2-1 to (b-1)*(b+1)". Is there a way to avoid this?
Valery