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docs(SpinRepresentations): drop roadmap Layer references from Suggested.lean - #290

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docs(SpinRepresentations): drop roadmap Layer references from Suggested.lean#290
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@kim-em kim-em commented Aug 27, 2026

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This PR removes the roadmap's "Layer" vocabulary from SpinRepresentations/Suggested.lean and replaces a chapter-wide Lawson-Michelsohn citation with a precise one.

Suggested.lean is a Lean code document, so it should use terms that fit in the final Lean source rather than roadmap planning concepts, per #225 (comment). All 32 Layer references are gone: section headings lose the Layer N: prefix, and each in-prose reference names the object it meant (Layer 3's bivectorLieRing becomes bivectorLieRing, the Layer-1 structure theorem becomes the structure theorem, Independent of Layers 6-8 becomes Independent of the exceptional isomorphisms, the real forms, and triality, and so on). Nothing outside the file referenced these headings.

The Lawson-Michelsohn entry now cites sections rather than the whole of Chapter I: §I.2 for Pin and Spin, §I.3 for the algebras, §I.4 for the classification, §I.5 for the representations, §I.10 for the (1,1)-periodicity theorem. cliff_bott gains the specific pointer: it is Theorem I.4.1 (4.3), the two recurrences it needs are (4.1) and (4.2), eight-periodicity is Theorem I.4.3 (4.11)-(4.12) with Cl(8,0) = M₁₆(ℝ) at (4.14), and the tables are Tables I and II.

It also records a trap: Lawson-Michelsohn's Cl(r,s) is this roadmap's Cliff(s, r). Their §I.4 (4.0) sets Cl(1,0) = ℂ and Cl(0,1) = ℝ ⊕ ℝ, while the base entries here are Cliff(1,0) ≅ ℝ × ℝ and Cliff(0,1) ≅ ℂ. Anyone following the citation without that note gets the mirror image of the table.

Every claim above was checked against the book rather than recalled: §I.4 pp. 25-29, including the section list on the contents page.

Only comments and docstrings change; no target, signature or statement is touched.

🤖 Prepared with Claude Code

…ed.lean

Suggested.lean is a Lean code document, so it should use mathematical terms
rather than roadmap planning vocabulary. Replace all 32 "Layer" references
with the objects they name: section headings lose the "Layer N:" prefix, and
in-prose references name the declaration or theorem instead.

Also give Lawson-Michelsohn a precise citation in place of a chapter-wide
one: the classification is §I.4, with Theorem 4.1 for the three recurrences
(cliff_bott is their (4.3)), Theorem 4.3 for eight-periodicity, and Tables I
and II for the tables. Record that their Cl(r,s) is this roadmap's
Cliff(s, r), since §I.4 (4.0) sets Cl(1,0) = ℂ against Cliff(1,0) = ℝ × ℝ
here; following the citation without that note gives the mirror image.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
@kim-em
kim-em requested a review from a team as a code owner August 27, 2026 13:26
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tauceti-review-bot Bot enabled auto-merge (squash) August 27, 2026 13:26
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