Hacktoberfest 2026: the issues maintainers tagged for October, open and beginner-friendly. Browse Hacktoberfest issues

calvo.md and calvo_machine_learn.md: $L^2$ definition removed but notation still used

Open
  • Is something wrong?
#328 0 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
68/100
Issue type
Documentation
Clarity
Mostly clear
Activity status
Quiet
Tech stack
latex, markdown
Domain
documentation

Research direction

Start with the affected sections in lectures/calvo.md and lectures/calvo_machine_learn.md, then review PR #312 to understand why the L^2 definition was removed. Decide whether the intended assumption is a restored definition, bounded sequences, or a cross-link, and apply that choice to all listed occurrences. Check the rendered lecture text to confirm no undefined L^2 references remain.

Written by the indexing model from the issue text.

Description

Summary

PR #312 ("[amss] Update Tom's edits to AMSS and Calvo Lectures") removed the local definition of square-summable / $L^2$ from the three Calvo lectures, but several places still use the $L^2$ notation without a definition, leaving readers without context for what space is being referenced.

Locations still using L^2 after the definition was removed

lectures/calvo.md — 7 occurrences
Line Context
330 $\vec \mu =\{\mu_t\}_{t=0}^\infty \in L^2$ into an inflation sequence
331 $\vec \theta = \{\theta_t\}_{t=0}^\infty \in L^2$.
334 $\vec v = \{v_t\}_{t=0}^\infty \in L^2$ that satisfies
340 sequence $\vec \mu \in L^2$.
342 At this point $\vec \mu \in L^2$ is an arbitrary exogenous policy.
453 $\{x_{t+1}, \mu_t \}_{t=0}^\infty$ sequences, with each sequence belonging to $L^2$:
460 where we require that $\{x_{t+1}, \mu_t \}_{t=0}^\infty \in L^2 \times L^2 .$
lectures/calvo_machine_learn.md — 1 occurrence
Line Context
208 \vec \theta \in L^2
lectures/calvo_abreu.md — clean

calvo_abreu.md had the same definition removed and no remaining $L^2$ references, so it's consistent.

Why it matters

Earlier in each affected lecture, the assumption on $\vec\mu$ was weakened from "square-summable" to "bounded" (a reasonable simplification — the discounted geometric structure of the forward solution is well-defined under boundedness). But the later sections that still use $L^2$ now reference an undefined space. A reader going top-to-bottom encounters $\vec\mu \in L^2$ at line 330+ in calvo.md with no prior definition or external pointer.

Suggested fix

Either:

  1. Reintroduce a brief $L^2$ definition in each of the two affected lectures (could be a one-liner: "$L^2$ denotes the space of square-summable sequences"), or
  2. Replace the remaining $L^2$ references with the weaker "bounded" framing if that's now the intended assumption end-to-end, or
  3. Cross-link to a single canonical definition in one of these lectures and have the others reference it.

Context

Surfaced by GitHub Copilot's PR review during sync of these lectures into lecture-dp (QuantEcon/lecture-dp#11). The PR is byte-identical to this repo's current main, so this issue belongs upstream.

🤖 Generated with Claude Code

Dominant language
TeX
Stars
37
Forks
26
Avg merge
2d 17h
Merged PRs (30d)
2

Getting set up

We have not checked this project's setup files yet. Start from its README, and see our first-contribution guide for the general steps.

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

More from QuantEcon/lecture-python-advanced.myst

All issues in QuantEcon/lecture-python-advanced.myst

Similar issues

More Documentation issues

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.