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#1684 spurious Principal Value message

closed
nobody
None
5
2009-11-29
2009-06-05
Barton Willis
No

(%i1) assume(p > 0);
(%o1) [p>0]

OK:

(%i4) integrate(exp(-p * t^2),t,minf,inf);
(%o4) sqrt(%pi)/sqrt(p)

OK, but not a principle value:

(%i5) integrate(exp(-pp * t^2),t,minf,inf);
Is pp positive, negative, or zero?pos;
Principal Value
(%o5) sqrt(%pi)/sqrt(pp)

Discussion

  • The difference between the two cases is in poles-in-interval. In the first case, there are no poles in the interval. In the second case, poles-in-interval thinks there are poles at minf and inf. Hence, maxima thinks we have a principal value integral.

     
  • Dieter Kaiser
    Dieter Kaiser
    2009-11-14

    This problem seems to be no longer present in Maxima 5.19post:

    (%i2) integrate(exp(-pp * t^2),t,minf,inf);
    Is pp positive, negative, or zero?

    p;
    (%o2) sqrt(%pi)/sqrt(pp)

    Setting the status to pending and resolution to "works for me".

    Dieter Kaiser

     
  • Dieter Kaiser
    Dieter Kaiser
    2009-11-14

    • status: open --> pending
     
  • This Tracker item was closed automatically by the system. It was
    previously set to a Pending status, and the original submitter
    did not respond within 14 days (the time period specified by
    the administrator of this Tracker).

     
    • status: pending --> closed