About inequalities



Hi,

I'm trying to understand the following behaviour:

/*********** begin maxima session ************/

(%i1) negp(u):=if asksign(u)='neg then true$
(%i2) posp(u):=if asksign(u)='pos then true$
(%i3) matchdeclare([a,b],true,c,negp,d,posp)$
(%i4) tellsimpafter((a<b)*c,a*c>b*c)$
(%i5) tellsimpafter((a<b)*d,a*d<b*d)$
Is  d  positive, negative, or zero?

/*********** end maxima session ************/

I can't understand why maxima asks for the sign of 'd'. It doesn't ask
anything about 'c'.

The above code was taken from share/simplifications/ineq.mac

When I load this package, I'm asked a lot of times for the sign of 'd',
since there are many rules involving this variable.


-- 
Mario Rodriguez Riotorto
www.biomates.net