[lqcontrol] style guide review and updated maths

[matheusvillasb]

-Proofread, checked all links and references
-Updated maths to style guide
-Added a few comments to solve questions I had while reading the document

[mmcky]

@matheusvillasb -- @HumphreyYang has answers to the questions you asked here #609 (comment) from #609.

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[mmcky]

@matheusvillasb the syntax around links wasn't formatted correctly. Checkout https://manual.quantecon.org/styleguide/doclinks.html and a99a241

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[mmcky]

@matheusvillasb this lecture has quite a few style guide violations such as

• check headings and adjust for https://manual.quantecon.org/styleguide/writing.html#titles-and-headings

Do you mind doing another pass? Note: there have been edits to this branch so you should git pull origin edit-lqcontrol before making any additional changes.

@HumphreyYang I see there is a model in this lecture. Do you think we should use NamedTuple (in similar style to the JAX conversions)?

[HumphreyYang]

@HumphreyYang I see there is a model in this lecture. Do you think we should use NamedTuple (in similar style to the JAX conversions)?

Many thanks @matheusvillasb and @mmcky,

Yes, I think it would be better by putting these argument into a class LQParams(NamedTuple) instead of globals:

r = 0.05
β = 1 / (1 + r)
T = 45
c_bar = 2
σ = 0.25
μ = 1
q = 1e6

[matheusvillasb]

@matheusvillasb this lecture has quite a few style guide violations such as

• check headings and adjust for https://manual.quantecon.org/styleguide/writing.html#titles-and-headings

Do you mind doing another pass? Note: there have been edits to this branch so you should git pull origin edit-lqcontrol before making any additional changes.

@HumphreyYang I see there is a model in this lecture. Do you think we should use NamedTuple (in similar style to the JAX conversions)?

@mmcky I'll do that! Thank you for picking these issues.

[matheusvillasb]

@mmcky

Do you mind doing another pass? Note: there have been edits to this branch so you should git pull origin edit-lqcontrol before making any additional changes.

So just to be sure, I need to do this while on my branch, right? Not on main.

Also, I tried to create a new branch to edit the lecture that follows this one. When I type git status, this is what I get:

PS C:\Users\mathe\QuantEcon_Lectures_Improvement\lecture-python.myst> git status
On branch edit-lqcontrol
Changes not staged for commit:
(use "git add ..." to update what will be committed)
(use "git restore ..." to discard changes in working directory)
modified: lectures/lagrangian_lqdp.md

no changes added to commit (use "git add" and/or "git commit -a")

Is this correct? The impression I have is that the edits in lagrangian_lqdp.md were made in the branch for the lqcontrol lecture instead of the branch I created for lagrangian_lqdp.

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[jstac]

🤖 Status note for a future session — from a maintainer investigation on 2026-07-08 into why open-PR previews 404. Context only, not instructions.

Netlify preview: https://pr-613--sunny-cactus-210e3e.netlify.app/ currently returns 404.

Why previews are down (repo-wide findings)

1. This branch is stale — 178 commits behind main. A preview build compiles the whole site from this branch. This branch's lectures/house_auction.md still has unpinned !pip install prettytable, which now breaks on a wcwidth incompatibility. main fixed this on 2026-06-28 by pinning prettytable<3.18 (#939). This alone fails any rebuild of this branch until it's updated to main.

2. The arviz failure was a red herring — do NOT pin arviz or rewrite plotting. A 2026-07-07 rebuild also failed in ar1_bayes/ar1_turningpts with an arviz_plots figsize ValueError. That was a transient bug in an intermediate arviz-plots 1.x release, already fixed in arviz 1.2.0. Verified locally on a clean latest-stack venv: the real az.plot_trace(trace) cell (pymc + numpyro InferenceData) runs green. The lectures use only 1.x-compatible arviz APIs (plot_trace, summary, from_numpyro, compare).

Recommended first step for this PR

Update this branch to main (merge or rebase — pulls in #939 plus ~178 other commits), then let CI rebuild. On today's latest libraries the site builds clean, so the preview should return. house_auction is the known blocker; updating also picks up other since-merged fixes — rebuild and address any remaining per-lecture failures. Verify with:

curl -sI https://pr-613--sunny-cactus-210e3e.netlify.app/lqcontrol.html

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This PR touches: lqcontrol.md. Last CI build: success@2025-09-29. Branch: 178 commits behind main as of 2026-07-08.