revisions for interactive.p-adics

This commit is contained in:
queue-miscreant 2025-03-03 03:33:55 -06:00
parent fd57fa066e
commit f5ce842863
2 changed files with 60 additions and 9 deletions

View File

@ -1,8 +1,18 @@
--- ---
title: "Complex Embedding of *p*-adics"
description: |
Visualizing fractals generated by sending *p*-adics to the complex plane.
format:
html:
html-math-method: katex
categories:
- interactive
- algebra
--- ---
```{ojs} ```{ojs}
//| echo: false
{{< include ./showAdic.ojs >}} {{< include ./showAdic.ojs >}}
``` ```
@ -23,7 +33,7 @@ $$
f_N(d; p) = \sum_{n = 0}^N c^n e^{2\pi i \cdot [d_{n:0}]_p / p^{n + 1}} f_N(d; p) = \sum_{n = 0}^N c^n e^{2\pi i \cdot [d_{n:0}]_p / p^{n + 1}}
$$ $$
Assuming the first term dominates, one way of interpreting this is that we place numbers Assuming the first term dominates, this can be interpreted as placing numbers evenly
around the unit circle according to their one's place. around the unit circle according to their one's place.
Then, we offset each by smaller circles, each centered on the last, using more and more digits. Then, we offset each by smaller circles, each centered on the last, using more and more digits.
This produces a fractal pattern that looks like a wheel with *p* spokes. This produces a fractal pattern that looks like a wheel with *p* spokes.
@ -35,11 +45,15 @@ All of the odd numbers are at the left side of the diagram, since the leading te
is negative one. is negative one.
The odd numbers are further split into those of the forms $4k + 1$ and $4k + 3$. The odd numbers are further split into those of the forms $4k + 1$ and $4k + 3$.
Controls
--------
Each of the inputs corresponds to something from the above formula. Each of the inputs corresponds to something from the above formula.
- *b*, the base of the expansions. - *b*, the base of the expansions.
- Integers are converted to their representations in base *b*, - Each point is the expansion of an integer in base *b*,
which are sequences of digits (*d* in the above formula). which corresponds to a sequence of digits (*d* in the above formula).
- *p*, the base used in the embedding. - *p*, the base used in the embedding.
- The same *p* that appears in the above formula. - The same *p* that appears in the above formula.
- Truncations of digit sequences ($d_{n:0}$) are interpreted as strings in base *p*, - Truncations of digit sequences ($d_{n:0}$) are interpreted as strings in base *p*,
@ -47,9 +61,46 @@ Each of the inputs corresponds to something from the above formula.
- *c*, the geometric constant. - *c*, the geometric constant.
- Smaller *c* means more tightly packed points. - Smaller *c* means more tightly packed points.
Additionally, instead of using an integer base, you can also use either *κ*-adic representation. Note that only 1024 points are calculated, and that only fifteen terms of the series are used ($N = 15$).
If using an integer base, only one thousand twenty four (1024) points will be calculated.
Note also that only fifteen terms of the series are used ($N = 15$).
Suggestions
-----------
### Invariance of *b*
Set *b* and *p* to 2 and *c* to 0.55.
Slowly increase *p* to 3.
The pattern should largely remain the same, but appear to be rotated around.
Increasing *p* further shears the pattern into an indistinct line of points.
This shows that the embedding base *does* matter, but the way the expansions are constructed
gives rise to the pattern.
### Small Changes
With *c* sufficiently small (about 0.3), and *p* fixed at 2, changing *b* keeps the diagram
almost the same.
This is because many numbers get sent to the same place as others.
For example, when only considering the first term of the series, "1" and "3" are both mapped to
$e^{\pi i} = e^{3 \pi i}$
If you make *c* larger, you can notice that points disappear from the case when *p* is 2.
If the plot used a massive number of points, this difference wouldn't be as visible.
### Blooming flower, in reverse
Try cranking *b* and *p* up to 10 and set *c* to something around 0.2 so that you can
clearly see a decagon made of decagons
Then, strobe *p* down to its minimum value.
Notice the larger decagon and smaller decagons collapse into nonagons when *p* hits 9.
### Lesser Bases
Set *b* to 2 and *p* to 1.1, the lowest it can go.
Moving *c* back and forth, you should be able to see an interesting fractal.
[^1]: Taken from the paper "Fractal geometry for images of continuous embeddings of p-adic [^1]: Taken from the paper "Fractal geometry for images of continuous embeddings of p-adic

View File

@ -45,9 +45,9 @@ viewof base = Inputs.range([2, 10], {
label: "Base of expansions (b)", label: "Base of expansions (b)",
}); });
viewof embedBase = Inputs.range([2, 10], { viewof embedBase = Inputs.range([1.1, 10], {
value: 2, value: 2,
step: 0.2, step: 0.1,
label: "Embedding base (p)", label: "Embedding base (p)",
}); });