Enhanced Laplace transforms and desolve for Maxima

Mark,

I looked at your patch for abs_integrate, but not the patches for the
other files.

In unit_step_mult_simp, your code replaces xreduce('max, ...) with
code that duplicates the logic in max, I think. Is this a workaround
for a limitation in max? Do you have examples of integrands that do
not involve hstep that your code can handle that the current code
cannot?

My preference would be to *delete* the function unit_step_mult_simp
from abs_integrate. The regression test for abs_integration runs OK
without it; and as far as I know, unit_step_mult_simp isn't ever
really needed (it sometimes keeps expressions more simple). As much as
possible, I would like to keep abs_integrate focused on integration,
not a general scheme for simplifying signum & friends.

You didn't explain if your proposed changes to abs_integrate were
needed by the other patches. Of course, abs_integrate resides in
/share/contrib (for a good reason), so nothing in the Maxima's core
should depend on code in abs_integrate. If you need just derivative
divides integration for hstep, you can take care of that by giving
hstep an integrate property.

--Barton