2020-08-05 18:59:01 UTC, rjf:
>
> There are two square roots. In this (classic) integration
> example/bug, a choice has to be made. You know that 4 has
> two square roots, -2 and 2. The integrand, which also can
> be rewritten as sqrt ( 4-4*cos(x/2)^2) , has 2 square
> roots. Therefore there a
On 2020-08-05 15:49, NicoJG wrote:
> @rjf Isn't the square root defined to be positive?
> Sure: x^2=y <=> x=+/-sqrt(y)
> But I think you would never consider f(x):=sqrt(x) to have the codomain
> of all negative numbers.
> At least I would expect a CAS to interpret a square root to be positive.
>
On Wednesday, August 5, 2020 at 12:49:37 PM UTC-7, NicoJG wrote:
>
> @rjf Isn't the square root defined to be positive?
> Sure: x^2=y <=> x=+/-sqrt(y)
>
But I think you would never consider f(x):=sqrt(x) to have the codomain of
> all negative numbers.
>
With complex numbers, there's no concept
On Wednesday, August 5, 2020 at 2:16:37 PM UTC-7, Reimundo Heluani wrote:
>
> So the problem is simply that Sage does accept the string "wdegrevlex" as
> a
> term order but does not assign degrees. Calling it the right way works:
>
> sage: R = PolynomialRing(QQ, 'x0,x1,x2',
> order=TermOrder('w
On Aug 05, 'Reimundo Heluani' via sage-devel wrote:
This actually does look like a bug in Sage:
sage: R = PolynomialRing(GF(2), 'x0,x1,x2', order='wdegrevlex')
sage: R.inject_variables()
Defining x0, x1, x2
sage: J = R.ideal([x0*x1+x2])
sage: J
) failed: TypeError: zip argument #2 must support i
This actually does look like a bug in Sage:
sage: R = PolynomialRing(GF(2), 'x0,x1,x2', order='wdegrevlex')
sage: R.inject_variables()
Defining x0, x1, x2
sage: J = R.ideal([x0*x1+x2])
sage: J
) failed: TypeError: zip argument #2 must support iteration>
R.
On Aug 05, 'Reimundo Heluani' via sa
I agree with the general analysis, but I think the statement "Any answer
that supplies only one answer is wrong." goes too far. It may be the case
that sage works inherently in the complex domain, and is unable to
understand that elementary calculus and certain other fields want to remain
in t
@rjf Isn't the square root defined to be positive?
Sure: x^2=y <=> x=+/-sqrt(y)
But I think you would never consider f(x):=sqrt(x) to have the codomain of
all negative numbers.
At least I would expect a CAS to interpret a square root to be positive.
rjf schrieb am Mittwoch, 5. August 2020 um 20:
There are two square roots. In this (classic) integration example/bug, a
choice has
to be made. You know that 4 has two square roots, -2 and 2.
The integrand, which also can be rewritten as sqrt ( 4-4*cos(x/2)^2) ,
has 2 square roots.
Therefore there are two potential different values for t
On Aug 05, 'Reimundo Heluani' via sage-devel wrote:
I went to try to answer a question posted today in sage-support and
found this:
sage: P = PolynomialRing(QQ, 'x0,x1,x2')
sage: P = PolynomialRing(GF(2), 'x0,x1,x2')
sage: P.inject_variables()
Defining x0, x1, x2
sage: I = P.ideal(x0*x1+x2)
sag
I went to try to answer a question posted today in sage-support and found
this:
sage: P = PolynomialRing(QQ, 'x0,x1,x2')
sage: P = PolynomialRing(GF(2), 'x0,x1,x2')
sage: P.inject_variables()
Defining x0, x1, x2
sage: I = P.ideal(x0*x1+x2)
sage: I.reduce(x2)
x2
sage: R = PolynomialRing(GF(2), '
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