#17892: Sage cannot work with Maxima's symbolic limit
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   Reporter:  rws       |            Owner:
       Type:  defect    |           Status:  new
   Priority:  major     |        Milestone:  sage-6.6
  Component:  calculus  |         Keywords:
  Merged in:            |          Authors:
  Reviewers:            |  Report Upstream:  N/A
Work issues:            |           Branch:
     Commit:            |     Dependencies:
   Stopgaps:            |
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 Maxima gives back limit expressions in some integral computation but Sage
 has no idea what that is. Consequently, working with the expression leads
 to failure:
 {{{
 sage: u(t) = exp(-(t-a)^2/(2*s^2)) + exp(-(t-b)^2/(2*s^2)) ; u(t);
 sage: integral(u(t)*exp(-I*k*t), t, -infinity, +infinity, hold=False)
 -limit(1/2*sqrt(2)*sqrt(pi)*s*erf(1/2*(I*sqrt(2)*k*s^2 - sqrt(2)*a +
 sqrt(2)*t)/s)*e^(-1/2*k^2*s^2 - I*a*k) +
 1/2*sqrt(2)*sqrt(pi)*s*erf(1/2*(I*sqrt(2)*k*s^2 - sqrt(2)*b +
 sqrt(2)*t)/s)*e^(-1/2*k^2*s^2 - I*b*k), t, -Infinity, plus) +
 limit(1/2*sqrt(2)*sqrt(pi)*s*erf(1/2*(I*sqrt(2)*k*s^2 - sqrt(2)*a +
 sqrt(2)*t)/s)*e^(-1/2*k^2*s^2 - I*a*k) +
 1/2*sqrt(2)*sqrt(pi)*s*erf(1/2*(I*sqrt(2)*k*s^2 - sqrt(2)*b +
 sqrt(2)*t)/s)*e^(-1/2*k^2*s^2 - I*b*k), t, +Infinity, minus)
 sage: _.simplify_full()
 ...
 TypeError: ECL says: Error executing code in Maxima:
 }}}
 Presumably a symbolic limit function would be necessary, and to connect it
 with what Maxima gives back.

 Is there a smaller example?

--
Ticket URL: <http://trac.sagemath.org/ticket/17892>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica, 
and MATLAB

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