Lost signs in factorization of monomials

[tueda]

For monomials, it seems that the multivariate factorization algorithm drops the overall sign:

$ rings.repl
OpenJDK 64-Bit Server VM warning: Option AggressiveOpts was deprecated in version 11.0 and will likely be removed in a future release.
Loading...
Running Ammonite Repl
Rings 2.5.6: efficient Java/Scala library for polynomial rings.
@ implicit val ring = MultivariateRing(Z, Array("x", "y"))
ring: MultivariateRing[IntZ] = MultivariateRing(Z, Array("x", "y"), GREVLEX)

@ val p = ring("-2 * x * y")
p: MultivariatePolynomial[IntZ] = -2*x*y

@ Factor(p)
res2: PolynomialFactorDecomposition[MultivariatePolynomial[IntZ]] = (2)*(x)*(y)

@ res2.multiply() == p
res3: Boolean = false

@ res2.multiply() == -p
res4: Boolean = true

[PoslavskySV]

Thanks again for reporting! That was not a trivial bug... Just fixed it, will appear in brew within 30-60 minutes.

[tueda]

OK. Thanks for the fix!