Karim Belabas on Tue, 11 Feb 2014 17:09:03 +0100 |
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Re: Component [5] of prime ideal structure |
* Jeroen Demeyer [2014-02-11 11:34]: > gp> idealprimedec(nfinit(x^2+1), 5)[1][5] > %4 = > [2 -1] > > [1 2] > > What is the meaning of this? This is the multiplication table by the anti-uniformizer b. If mb := pr[5], then mb[,1] is the old value ( = b * nf.zk[1] = b ) > The documentation ??idealprimedec says > that it is supposed to be an algebraic integer, but I don't > understand > it. This changed from PARI-2.5 to PARI-2.6 and it breaks Denis > Simon's GP scripts. This was mentionned in CHANGES-C.27, but not in 'COMPAT', and ??idealprimedec had become inaccurate. I just fixed all that. If I understand correctly, the only reason this was needed in Denis's scripts is that we do not export the ZC_nfvalrem function that returns both the valuation *and* the part coprime to the prime ideal. The nfval() function (and the valuation() function for that matter) should take an extra optional argument to return that coprime part. Cheers, K.B. -- 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/~kbelabas/ F-33405 Talence (France) http://pari.math.u-bordeaux1.fr/ [PARI/GP] `