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2019-01-10 19:06:35 -0500 asked a question Homomorphisms lifted from base ring in PowerSeriesRing do not preserve precision

Hi all,

Homomorphisms which are lifted from the base ring seem to be unaware that precision exists in power/Laurent series rings. For example:

sage: R.<x> = PowerSeriesRing(ZZ)
sage: f = Hom(ZZ, ZZ)([1])
sage: Rf = Hom(R, R)(f); Rf
Ring endomorphism of Power Series Ring in x over Integer Ring
  Defn: Induced from base ring by
        Ring endomorphism of Integer Ring
          Defn: 1 |--> 1
sage: Rf(1 + x + O(x^2))
1 + x

Can someone confirm that the expected output should be 1 + x + O(x^2), and that this is a bug?

Thanks,

Henry

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2018-12-23 17:12:32 -0500 asked a question LaurentPolynomial can't factor constants

Hi all,

Many LaurentPolynomials throw errors when I try to factor them. For example:

sage: R.<x,y> = LaurentPolynomialRing(QQ)
sage: R.one().factor()
AttributeError: ...
sage: (x^-1).factor()
AttributeError: ...

This seems to come from the unit part of Polynomial.factor() sometimes (incorrectly) living in Integer Ring, and sometimes (correctly) living in whatever self.parent() is.

Is this intentional or a bug?

Thanks,

Henry