Easy fix at https://trac.sagemath.org/ticket/34653, please review!
Martin
On Thursday, 13 October 2022 at 00:05:37 UTC+2 Martin R wrote:
> OK, I think now I am down to what's quite clearly a bug:
>
> sage: P. = PolynomialRing(SR)
> sage: R. = PolynomialRing(P, sparse=False); R
> Univariate Polyn
OK, I think now I am down to what's quite clearly a bug:
sage: P. = PolynomialRing(SR)
sage: R. = PolynomialRing(P, sparse=False); R
Univariate Polynomial Ring in z over Multivariate Polynomial Ring in x, y
over Symbolic Ring
sage: A = -x*z^2 + x*z
sage: B = -x
sage: A // B
z^2 - z
sage: P. = Pol
Possibly related:
sage: P. = PolynomialRing(SR)
sage: R. = PolynomialRing(P); R
Univariate Polynomial Ring in z over Multivariate Polynomial Ring in x, y
over Symbolic Ring
sage: num = -x*z^2 + x*z
sage: den = x*z^2 + (-x-1)*z + 1
sage: num.gcd(den)
z - 1
sage: P. = PolynomialRing(SR)
sage: R. =
Ah, thank you!
On Wednesday, 12 October 2022 at 23:19:09 UTC+2 David Roe wrote:
> It's the difference between conversion and coercion.
>
> P = PolynomialRing(GF(2), "z", sparse=True); Q = PolynomialRing(ZZ, "z",
> sparse=False)
> sage: P.convert_map_from(Q)
> Conversion map:
> From: Univariate
It's the difference between conversion and coercion.
P = PolynomialRing(GF(2), "z", sparse=True); Q = PolynomialRing(ZZ, "z",
sparse=False)
sage: P.convert_map_from(Q)
Conversion map:
From: Univariate Polynomial Ring in z over Integer Ring
To: Sparse Univariate Polynomial Ring in z over Fini
Sorry, I don't understand your last sentence. We have
sage: P = PolynomialRing(GF(2), "z", sparse=True); Q = PolynomialRing(ZZ,
"z", sparse=False)
sage: P.has_coerce_map_from(Q)
False
How does this fit with
"And of course you can convert even when Q is not sparse."?
Martin
On Wednesda
Yes, that's expected.
sage: P = PolynomialRing(GF(2), "z", sparse=True); Q = PolynomialRing(ZZ,
"z", sparse=True)
sage: P.has_coerce_map_from(Q)
True
And of course you can convert even when Q is not sparse.
David
On Wed, Oct 12, 2022 at 4:58 PM 'Martin R' via sage-devel <
sage-devel@googlegroups
I have no idea whether the following is to be expected:
sage: P = PolynomialRing(GF(2), "z", sparse=False); Q = PolynomialRing(ZZ,
"z")
sage: P.has_coerce_map_from(Q)
True
sage: P = PolynomialRing(GF(2), "z", sparse=True); Q = PolynomialRing(ZZ,
"z")
sage: P.has_coerce_map_from(Q)
Fal
I am not sure whether the following is to be expected.
Martin
sage: R. = SR[]
sage: S. = R[]
sage: (x*z).quo_rem(S(x))
---
TypeError Traceback (most recent call last)
File ~/sage-develop/src/sa
