Karim Belabas on Fri, 13 Jul 2012 08:51:36 +0200


[Date Prev] [Date Next] [Thread Prev] [Thread Next] [Date Index] [Thread Index]

Re: 2.5.1, 2.4.3 are missing solutions in conditional thue


* Georgi Guninski [2012-07-13 07:56]:
> Is this really a bug or I am missing something?

This is a bug. I am investigating this, and so is the original author,
Guillaume Hanrot. I do not understand where the problem (missing
solution) comes from yet. It looks like a mathematical bug so far...

Thanks for your report !

  K.B.

> On Sat, Jul 07, 2012 at 04:44:48PM +0300, Georgi Guninski wrote:
>> Some more testcases for 2.5.1/2.4.3:
>> 
>> pp=x^3 - 20*x^2 + 100*x + 1;a=3^3
>> pp=x^3 - 20*x^2 + 100*x + 1;a=2^3
>> pp=x^3 - 18*x^2 + 81*x + 1;a=2^3
>> pp=x^3 - 6*x^2 + 9*x + 1;a=1
>> pp=x^3 - 20*x^2 + 100*x + 1;a=1
>> 
>> (For $a=1$ 2.4.3 doesn't give any warning).
>> 
>> On Sat, Jul 07, 2012 at 03:34:50PM +0300, Georgi Guninski wrote:
>>> 2.5.1 and 2.4.3 on ubuntu x86_64.
>>> 
>>> ? p=x^3 - 18*x^2 + 81*x + 1;a=3^3
>>> %1 = 27
>>> ? t=thue(thueinit(p,0),a);[#t,t]
>>> %2 = [3, [[0, 3], [3, 0], [19, 2]]]
>>> ? t=thue(thueinit(p,1),a);[#t,t]
>>> %3 = [4, [[0, 3], [3, 0], [27, 3], [19, 2]]]
>>> 
>>> 2.5.1 doesn't give warning, 2.4.3 mentions GRH (surely incorrect).
-- 
Karim Belabas, IMB (UMR 5251)  Tel: (+33) (0)5 40 00 26 17
Universite Bordeaux 1          Fax: (+33) (0)5 40 00 69 50
351, cours de la Liberation    http://www.math.u-bordeaux1.fr/~belabas/
F-33405 Talence (France)       http://pari.math.u-bordeaux1.fr/  [PARI/GP]
`