# [Maxima] dynamically created symbol

Richard Fateman fateman at eecs.berkeley.edu
Mon Jul 2 09:33:08 CDT 2012

Looking back on this, I think that user-defined contexts are
unnecessary, or at least should be if
definite integration does the right thing.

On 6/29/2012 12:21 AM, Jérome Laurens wrote:

...

I have integrals like this

\int_{x=...}^{...} \int_{t=f(x)}^{...} foo(t,x) dt dx

But integrate tells me that it needs to know that f(x) is real
so I assume that x has some properties to ensure that f(x) is real
.......

We should agree that
integrate(f(t,x), t, a ,b)
has the same meaning as

integrate(f(gensym1,x), gensym1, a, b).

If defint does its job correctly, it should do this:

generate a context in which   a<= gensym1 <=b
and then run some algorithm.

I suspect Jerome's problem disappears if the name
of the variable of integration is not re-used.  This
can be easily remedied by using subst.  Probably a
finite list of variable names can be used. If it is
confirmed that a particular name is no longer in use, it
can be re-used.  Or perhaps it is obvious from some other
source that the integration will never be nested more than
100,  then 100 names can be used.

RJF