I chose the weighting (1 : g + 1 : 1) following Galbraith's 
textbook https://www.math.auckland.ac.nz/~sgal018/crypto-book/ch10.pdf when 
implementing the arithmetic on the Jacobian. This is not a "good" answer 
though.

I would love to hear from more people about what they use / would want to 
use. 

As for deprecations, I won't know exactly how much will change before I 
start working on this but if anyone's code fundamentally uses the fact it's 
a projective variety and the functions coming from this then I suppose 
everything will simply have to exist as a second class with deprecation 
warnings. I don't know what's best here.

Ultimately (even if I wait 2 years) I think it would be good for sage to 
have more functioning arithmetic on Jacobians but this is obviously a very 
small slice of pie in the whole meal of hyperellptic curves.

As one data point, the following magma code

```
R<x> := PolynomialRing(Rationals());
f := x^6 + x + 1;
H := HyperellipticCurve(f);
Ambient(H)
```

Outputs

Projective Space of dimension 2 over Rational Field
Variables: $.1, $.2, $.3
The grading is:
    1, 3, 1

Matching my proposed grading.

On Monday, March 11, 2024 at 9:52:09 PM UTC Nils Bruin wrote:

> The change makes sense, but you should investigate if it is at all 
> possible to do this going through normal deprecation procedures, which 
> would probably involve having both functionalities for some time (likely 
> via differently named methods or via a flag implemented in a 
> backward-compatime way), then having a deprecation period on the "old" 
> functionality. After that the deprecated functionality can be removed. 
> After a suitable wait period, the vacated space in the namespace can now be 
> used for the new method. You'll be taking a couple of years before you're 
> there.
>
> If it's not possible, you'd better have very good reasons to probably 
> break people's code out there with very little warning.
>
> Once you find a way to do this, there's another choice in convention to 
> consider: do you go with (1:1:g+1) weights or with (1:g+1:1) ? I.e., with 
> [X:Z:Y] or [X:Y:Z]. Both have precedent and people who are used to the 
> other convention will find it really annoying to adjust.
>
>

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