sagemathgh-37125: compute isogeny kernel polynomials from irreducible divisors or (possibly irrational) points
    
In this patch we implement Algorithms 3 and 4 from [this
paper](https://ia.cr/2023/106). Evidently, the necessity for such an
algorithm arises when converting from endomorphism-ring ideals to
isogenies.

One immediate application is that `isogenies_prime_degree_general()` can
be simplified, even with a small speedup:

```sage
sage: K.<i> = QuadraticField(-1)
sage: E = EllipticCurve(K,[0,0,0,1,0])
sage: %timeit E.isogenies_prime_degree(37)
````
Before: `2.39 s ± 3.31 ms per loop (mean ± std. dev. of 7 runs, 1 loop
each)`
After: `2.29 s ± 5.05 ms per loop (mean ± std. dev. of 7 runs, 1 loop
each)`

#sd123
    
URL: sagemath#37125
Reported by: Lorenz Panny
Reviewer(s): John Cremona

sagemathgh-37125: compute isogeny kernel polynomials from irreducible divisors or (possibly irrational) points
    
In this patch we implement Algorithms 3 and 4 from [this
paper](https://ia.cr/2023/106). Evidently, the necessity for such an
algorithm arises when converting from endomorphism-ring ideals to
isogenies.

One immediate application is that `isogenies_prime_degree_general()` can
be simplified, even with a small speedup:

```sage
sage: K.<i> = QuadraticField(-1)
sage: E = EllipticCurve(K,[0,0,0,1,0])
sage: %timeit E.isogenies_prime_degree(37)
````
Before: `2.39 s ± 3.31 ms per loop (mean ± std. dev. of 7 runs, 1 loop
each)`
After: `2.29 s ± 5.05 ms per loop (mean ± std. dev. of 7 runs, 1 loop
each)`

#sd123
    
URL: sagemath#37125
Reported by: Lorenz Panny
Reviewer(s): John Cremona

sagemathgh-37125: compute isogeny kernel polynomials from irreducible divisors or (possibly irrational) points
    
In this patch we implement Algorithms 3 and 4 from [this
paper](https://ia.cr/2023/106). Evidently, the necessity for such an
algorithm arises when converting from endomorphism-ring ideals to
isogenies.

One immediate application is that `isogenies_prime_degree_general()` can
be simplified, even with a small speedup:

```sage
sage: K.<i> = QuadraticField(-1)
sage: E = EllipticCurve(K,[0,0,0,1,0])
sage: %timeit E.isogenies_prime_degree(37)
````
Before: `2.39 s ± 3.31 ms per loop (mean ± std. dev. of 7 runs, 1 loop
each)`
After: `2.29 s ± 5.05 ms per loop (mean ± std. dev. of 7 runs, 1 loop
each)`

#sd123
    
URL: sagemath#37125
Reported by: Lorenz Panny
Reviewer(s): John Cremona

sagemathgh-37125: compute isogeny kernel polynomials from irreducible divisors or (possibly irrational) points
    
In this patch we implement Algorithms 3 and 4 from [this
paper](https://ia.cr/2023/106). Evidently, the necessity for such an
algorithm arises when converting from endomorphism-ring ideals to
isogenies.

One immediate application is that `isogenies_prime_degree_general()` can
be simplified, even with a small speedup:

```sage
sage: K.<i> = QuadraticField(-1)
sage: E = EllipticCurve(K,[0,0,0,1,0])
sage: %timeit E.isogenies_prime_degree(37)
````
Before: `2.39 s ± 3.31 ms per loop (mean ± std. dev. of 7 runs, 1 loop
each)`
After: `2.29 s ± 5.05 ms per loop (mean ± std. dev. of 7 runs, 1 loop
each)`

#sd123
    
URL: sagemath#37125
Reported by: Lorenz Panny
Reviewer(s): John Cremona

sagemathgh-37262: Added automatic size labeler
    
I have implemented the `automatic size labeler`, which now assigns
labels to pull requests based on the number of lines changed

**Minimal**
Typically involves very small changes, bug fixes, or updates that
require only a few lines of code, often less than 50.
sagemath#37208 sagemath#37146 sagemath#37043

**Small**
Involves more substantial changes than minimal, potentially adding new
features or making modifications to existing ones. The range is usually
between 50 to 100 lines of code.
sagemath#37152 sagemath#37132

**Moderate**
Represents a significant portion of the codebase being modified, such as
adding new features, refactoring, or making extensive changes to
existing functionalities. This might involve between 100 to 300 lines of
code.
sagemath#36919 sagemath#37112

**Large**
Involves substantial and complex changes across various parts of the
codebase. This could include major architectural changes, the
introduction of new modules, or a significant overhaul of existing
features, often exceeding 300 lines of code.
sagemath#37125 sagemath#36977 sagemath#36972

### 📝 Checklist

<!-- Put an `x` in all the boxes that apply. -->
<!-- If your change requires a documentation PR, please link it
appropriately -->
<!-- If you're unsure about any of these, don't hesitate to ask. We're
here to help! -->
<!-- Feel free to remove irrelevant items. -->

- [x] The title is concise, informative, and self-explanatory.
- [x] The description explains in detail what this PR is about.
- [x] I have linked a relevant issue or discussion.

Fixes: sagemath#37254
    
URL: sagemath#37262
Reported by: Aman Moon
Reviewer(s): Sebastian Oehms

sagemathgh-37262: Added automatic size labeler
    
I have implemented the `automatic size labeler`, which now assigns
labels to pull requests based on the number of lines changed

**Minimal**
Typically involves very small changes, bug fixes, or updates that
require only a few lines of code, often less than 50.
sagemath#37208 sagemath#37146 sagemath#37043

**Small**
Involves more substantial changes than minimal, potentially adding new
features or making modifications to existing ones. The range is usually
between 50 to 100 lines of code.
sagemath#37152 sagemath#37132

**Moderate**
Represents a significant portion of the codebase being modified, such as
adding new features, refactoring, or making extensive changes to
existing functionalities. This might involve between 100 to 300 lines of
code.
sagemath#36919 sagemath#37112

**Large**
Involves substantial and complex changes across various parts of the
codebase. This could include major architectural changes, the
introduction of new modules, or a significant overhaul of existing
features, often exceeding 300 lines of code.
sagemath#37125 sagemath#36977 sagemath#36972

### 📝 Checklist

<!-- Put an `x` in all the boxes that apply. -->
<!-- If your change requires a documentation PR, please link it
appropriately -->
<!-- If you're unsure about any of these, don't hesitate to ask. We're
here to help! -->
<!-- Feel free to remove irrelevant items. -->

- [x] The title is concise, informative, and self-explanatory.
- [x] The description explains in detail what this PR is about.
- [x] I have linked a relevant issue or discussion.

Fixes: sagemath#37254
    
URL: sagemath#37262
Reported by: Aman Moon
Reviewer(s): Sebastian Oehms

sagemathgh-37262: Added automatic size labeler
    
I have implemented the `automatic size labeler`, which now assigns
labels to pull requests based on the number of lines changed

**Minimal**
Typically involves very small changes, bug fixes, or updates that
require only a few lines of code, often less than 50.
sagemath#37208 sagemath#37146 sagemath#37043

**Small**
Involves more substantial changes than minimal, potentially adding new
features or making modifications to existing ones. The range is usually
between 50 to 100 lines of code.
sagemath#37152 sagemath#37132

**Moderate**
Represents a significant portion of the codebase being modified, such as
adding new features, refactoring, or making extensive changes to
existing functionalities. This might involve between 100 to 300 lines of
code.
sagemath#36919 sagemath#37112

**Large**
Involves substantial and complex changes across various parts of the
codebase. This could include major architectural changes, the
introduction of new modules, or a significant overhaul of existing
features, often exceeding 300 lines of code.
sagemath#37125 sagemath#36977 sagemath#36972

### 📝 Checklist

<!-- Put an `x` in all the boxes that apply. -->
<!-- If your change requires a documentation PR, please link it
appropriately -->
<!-- If you're unsure about any of these, don't hesitate to ask. We're
here to help! -->
<!-- Feel free to remove irrelevant items. -->

- [x] The title is concise, informative, and self-explanatory.
- [x] The description explains in detail what this PR is about.
- [x] I have linked a relevant issue or discussion.

Fixes: sagemath#37254
    
URL: sagemath#37262
Reported by: Aman Moon
Reviewer(s): Sebastian Oehms

sagemathgh-40467: compute minimal polynomial of an isogeny & push such polynomials through other isogenies
    
Back in sagemath#37125 we implemented Algorithms 3 and 4 from [Deuring for the
People](https://ia.cr/2023/106). In this patch we add Algorithm 5, as
well as a simple convenience method to compute the minimal polynomial of
an isogeny.

This functionality is very convenient for computing chains of isogenies
whose kernel points may live in extension fields — without explicitly
constructing and working in those extension fields.
    
URL: sagemath#40467
Reported by: Lorenz Panny
Reviewer(s): Giacomo Pope

sagemathgh-40467: compute minimal polynomial of an isogeny & push such polynomials through other isogenies
    
Back in sagemath#37125 we implemented Algorithms 3 and 4 from [Deuring for the
People](https://ia.cr/2023/106). In this patch we add Algorithm 5, as
well as a simple convenience method to compute the minimal polynomial of
an isogeny.

This functionality is very convenient for computing chains of isogenies
whose kernel points may live in extension fields — without explicitly
constructing and working in those extension fields.
    
URL: sagemath#40467
Reported by: Lorenz Panny
Reviewer(s): Giacomo Pope

sagemathgh-40467: compute minimal polynomial of an isogeny & push such polynomials through other isogenies
    
Back in sagemath#37125 we implemented Algorithms 3 and 4 from [Deuring for the
People](https://ia.cr/2023/106). In this patch we add Algorithm 5, as
well as a simple convenience method to compute the minimal polynomial of
an isogeny.

This functionality is very convenient for computing chains of isogenies
whose kernel points may live in extension fields — without explicitly
constructing and working in those extension fields.
    
URL: sagemath#40467
Reported by: Lorenz Panny
Reviewer(s): Giacomo Pope

sagemathgh-40467: compute minimal polynomial of an isogeny & push such polynomials through other isogenies
    
Back in sagemath#37125 we implemented Algorithms 3 and 4 from [Deuring for the
People](https://ia.cr/2023/106). In this patch we add Algorithm 5, as
well as a simple convenience method to compute the minimal polynomial of
an isogeny.

This functionality is very convenient for computing chains of isogenies
whose kernel points may live in extension fields — without explicitly
constructing and working in those extension fields.
    
URL: sagemath#40467
Reported by: Lorenz Panny
Reviewer(s): Giacomo Pope

sagemathgh-40467: compute minimal polynomial of an isogeny & push such polynomials through other isogenies
    
Back in sagemath#37125 we implemented Algorithms 3 and 4 from [Deuring for the
People](https://ia.cr/2023/106). In this patch we add Algorithm 5, as
well as a simple convenience method to compute the minimal polynomial of
an isogeny.

This functionality is very convenient for computing chains of isogenies
whose kernel points may live in extension fields — without explicitly
constructing and working in those extension fields.
    
URL: sagemath#40467
Reported by: Lorenz Panny
Reviewer(s): Giacomo Pope