bug in multivariate factorization

[mlee]

Dear Singular-Team,

in Sage, I occasionally experienced a crash when doing multivariate polynomial factorisation with coefficients GF(2). "Occasionally" means that one and the same example sometimes works and sometimes doesn't. The probability of it occurring seems to increase if there was previously a KeyboardInterrupt?.

The "last words" before the crash are: convertFacCF2NTLGF2X: coefficient not immidiate!

So, why am I writing this here? The error seems to be known to the macaulay2 list (and they have a reproducibly failing example): ​http://groups.google.com/group/macaulay2/browse_thread/thread/c3311f3bed1aab8e/3b14dea9e2dfe798

There, Dan Grayson wrote: """ The error message comes from Singular Libfac, the library from Singular written by Michael Messollen that computes characteristic series. It might be a bug in that library, since if I try replacing 2 by 101, there is no problem like this. """

Assuming that Dan is right and the error is from Singular: Are you aware of this bug? Will it be resolved in the next release?

Best regards, Simon

[hannes]

see #131