This isn’t an answer, but FWIW, I checked this on sage versions back to 8.3, and get the same result.
I also checked, on an older (“Yosemite”) system with sage 7.3, and that worked as you expect. I don’t have time to dig into this, though. HTH, Justin PS: All these were on Macs. > On Feb 27, 2020, at 23:02 , 'Benjamin Matschke' via sage-nt > <[email protected]> wrote: > > Dear all, > > The following code raises a ValueError: [*some big element of L*] is not an > S-unit. > > L.<theta_L> = NumberField(x^6 - 68463*x^4 - 5120808*x^3 + 1250774892*x^2 + > 192368273328*x + 7520491439712) > OLSstar = UnitGroup(L,proof=False,S=tuple(L.primes_above(2*5*7*13))) > u = OLSstar.gen(11) > print(u) # yields u11 > print(L(u)) # yields some very large element of L > print(OLSstar(L(u))) # raises a ValueError > > The last output should of course be u11 again. The above is the simplest > example that I could extract. I have other examples, where the composed > coersion from OLSstar to L and back to OLSstar is not the identity (according > to sage, sometimes a minus is falsely introduced), although it should. I do > not know where the error comes from. > > Sometimes UnitGroup() also raises a PariError, which comes from bnfsunit() > within UnitGroup.__init__(), which can be resolved by increasing pari's > precision. The above error however persists after increasing pari's precision > generously. > > This was run on Sage 9.0, Linux Mint 19.3. Any help is appreciated. > > Thanks, > Benjamin > > -- > You received this message because you are subscribed to the Google Groups > "sage-nt" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sage-nt/276bbea0-ca70-411b-b2f9-f8ced377c7c2%40googlegroups.com. -- Justin C. Walker Curmudgeon at Large Director Institute for the Enhancement of the Director's Income -- Build a man a fire and he'll be warm for a night. Set a man on fire and he'll be warm for the rest of his life. -- You received this message because you are subscribed to the Google Groups "sage-nt" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-nt/1EDB9F59-54BC-4856-B861-3ACDB6E43AC4%40mac.com.
