Minor shortcoming in integration

[Martin R]

FriCAS integration routines know dilog and in general seem to be able to handle them.  Howewer, we have

(1) -> ex := integrate(polylog(3, x), x)

   (1)

                 log(- x + 1)

   - x %iint(x,- ------------) + x polylog(3,x) + (- x + 1)log(- x + 1) + x

                       x

                                         Type: Union(Expression(Integer),...)

(2) -> D(ex,x) - polylog(3, x)

                    log(- x + 1)

   (2)  - %iint(x,- ------------) + dilog(- x + 1)

                          x

                                                    Type: Expression(Integer)

So, for some reason, the integrator returns an unevaluated integral as %iint, and moreover doesn't recognize that this integral is in fact dilog(1-x).

Martin

[Waldek Hebisch]

Thanks for info. I also noticed this. Internaly polylogs (and
other Liouvilian functions) are represented using %iint, but
there is a problem with translating back.

--
Waldek Hebisch