Karim BELABAS on Sat, 08 Nov 2003 13:00:56 +0100 |
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Re: polgalois() inconsistency |
On Fri, 7 Nov 2003, Igor Schein wrote: > ? default(new_galois_format,0) > new_galois_format = 0 (off) > ? polgalois(x^3-2) > [6, -1, 2] > ? default(new_galois_format,1) > new_galois_format = 1 (on) > ? polgalois(x^3-2) > [6, -1, 2] > > I expect the first result to say [6,-1,1] according to the manual. > Also, in the manual both new_galois_format and newgaloisformat occur. > I guess the former is correct. I hadn't noticed that: from the normalized output (new_galois_format = 1), there's no way to distinguish S_3 as a subgroup of S_3 (i.e polynomial of degree 3) and as a subgroup of S_6 (poly of degree 6). And in the old format, they get two different names. So the way I implemented new_galois_format (get normalized result, then translate for backward compatibility if necessary) can't work because of this single example. polgalois itself has to know about new_galois_format. Fixed in CVS [ and checked / taken into account in 'make test-galois' ]. Karim. -- Karim Belabas Tel: (+33) (0)1 69 15 57 48 Dép. de Mathématiques, Bât. 425 Fax: (+33) (0)1 69 15 60 19 Université Paris-Sud http://www.math.u-psud.fr/~belabas/ F-91405 Orsay (France) http://pari.math.u-bordeaux.fr/ [PARI/GP]