Neglectring terms



Hi,

I'm wondering if there if it is possible to make Maxima neglect small 
terms from a sum based on their numerical values and a threshold value 
that tells the function when it is ok to neglect a term ? The condition 
for neglecting terms could be defined as term/max(terms) <  threshold
Example:

neglect(a*b+a+b, [a=1e-2, b=1e-4] , 1e3) would give
a+b

Regards

Henrik Johansson