Codex — v0.5 Lateral Expansion Plan
v0.x scope is complete: 66 units, fully closed DAG, spin-geometry strand (Wave 1) traversable from leaf to apex with three tiers. v0.5 is the first lateral expansion: producing additional apex strands beyond spin geometry to reach Fast Track parity.
Read docs/plans/PILOT_PLAN.md (v0.x retrospective), docs/plans/WAVE_3_PLAN.md and docs/plans/WAVE_4_PLAN.md (depth-completion plans), docs/pilot-lessons.md (consolidated production lessons), docs/specs/QUALITY_RUBRIC.md (the validator gate).
1. v0.5 scope
Five additional apex strands selected for breadth, canonisation, and tractability. Each strand:
- Has 8–15 apex units culminating in a major synthesis theorem.
- Pulls in 10–25 supporting units, most of whose foundations are already shipped in v0.x (smooth manifold, vector bundle, Lie group, de Rham cohomology, etc.).
- Has well-defined Master-tier anchor texts from the Fast Track booklist.
- Produces in roughly the same footprint as the original spin-geometry pilot (~30–40 units total per strand) but at substantially faster cadence because the foundational prereq chain is already in place.
The five strands:
| # | Strand | Apex synthesis | Anchors | Est. units |
|---|---|---|---|---|
| A | Algebraic geometry | Riemann-Roch + Hodge decomposition + sheaf cohomology | Hartshorne; Griffiths-Harris; Voisin; Vakil | ~35 |
| B | Symplectic geometry | Moment map + symplectic reduction + Floer homology | Arnold; Audin; Cannas da Silva; Donaldson-Kronheimer | ~30 |
| C | Riemann surfaces & complex analysis | Riemann-Roch for curves + Abel-Jacobi + uniformisation | Donaldson Riemann Surfaces; Forster; Farkas-Kra; Ahlfors-Sario | ~25 |
| D | Representation theory | Borel-Weil-Bott + Peter-Weyl + classification of compact simple Lie groups | Fulton-Harris; Serre Linear Reps; Knapp; Bump | ~30 |
| E | Statistical field theory & lattice models | Onsager 2D Ising + RG flow + phase transitions | Baxter; Itzykson-Drouffe; Kardar (MIT OCW 8.334) | ~25 |
Estimated total v0.5 production: ~145 units across 5 strands. Combined with v0.x's 66 units, that's ~210 units total — roughly Fast Track parity for the full modern-geometry section.
2. Strand A — Algebraic geometry
Apex synthesis: Riemann-Roch, sheaf cohomology, Hodge theory.
Apex units (Wave 1 equivalent)
04.01.??Sheaf — algebraic / topological foundation.04.01.??Coherent sheaf on a scheme.04.02.??Scheme — affine, gluing, examples.04.02.??Morphism of schemes.04.03.??Sheaf cohomology (Čech, derived functor).04.03.??Serre's vanishing theorem.04.04.??Divisor on a curve.04.04.??Riemann-Roch theorem (curves, then surfaces).04.05.??Hodge decomposition.04.05.??Kähler manifold.04.06.??Algebraic curve as Riemann surface (link to Strand C).
Wave 2 supporting units (unique to AG)
- Commutative ring + ideal (extends our
03.01.02 / 03.01.03) - Localisation
- Tensor product over a ring
- Zariski topology
- Spectrum of a ring
Spec(A) - Quasi-coherent sheaf
- Locally free sheaf / vector bundle on scheme
- Étale topology (placeholder — full étale is v1+)
- Algebraic variety (classical)
- Projective space + projective scheme
- Line bundle on projective scheme (Picard group)
- Riemann's theorem on algebraic curves
- Ext / Tor functors
Foundations already shipped (reuse)
- Topological space, continuous map, metric space
- De Rham cohomology, exterior derivative, Stokes' theorem
- Differential forms, smooth manifold
- Vector space, field, group, ring (function from gpt-codex's Wave 4 batch)
- Tensor product, tensor algebra, quotient algebra, ideal
- Homotopy, covering space
Estimated breakdown
- Apex: 11 units
- New supporting: ~13 units
- Reused foundations: substantial (no new production needed)
- Total new production: ~24 units
Owner: claude (one of three claude strands)
3. Strand B — Symplectic geometry
Apex synthesis: Moment map theory, symplectic reduction, applications to Hamiltonian dynamics and Floer homology.
Apex units (Wave 1 equivalent)
05.01.??Symplectic vector space (linear algebra).05.01.??Symplectic manifold.05.02.??Hamiltonian vector field + symplectic vector field.05.02.??Poisson bracket + Poisson manifold.05.03.??Coadjoint orbit.05.04.??Moment map.05.04.??Marsden-Weinstein symplectic reduction.05.05.??Lagrangian submanifold.05.06.??Almost-complex structure on a symplectic manifold.05.07.??Gromov non-squeezing theorem.05.08.??Arnold conjecture (statement) → Floer homology setup.
Wave 2 supporting units (unique to SG)
- Integrable system (Liouville-Arnold)
- Action-angle coordinates
- Cotangent bundle as canonical symplectic manifold
- Darboux's theorem
- Symplectic group (Lie group; reuses
03.03.01) - Maslov index
- Pseudoholomorphic curve (J-holomorphic curve)
- Symplectic capacity
- Conley-Zehnder index
- Floer homology (Hamiltonian / instanton flavors)
Foundations already shipped (reuse)
- Smooth manifold, differential forms, exterior derivative
- Lie group, Lie algebra, Lie group action
- Bilinear form (skew-symmetric variant for symplectic forms)
- De Rham cohomology
- Hamilton's principle and variational calculus
Estimated breakdown
- Apex: 11 units
- New supporting: ~10 units
- Total new production: ~21 units
Owner: gpt-codex (one of two gpt-codex strands)
4. Strand C — Riemann surfaces & complex analysis
Apex synthesis: Riemann-Roch for compact Riemann surfaces, Abel-Jacobi map, uniformisation theorem.
Apex units (Wave 1 equivalent)
06.01.??Holomorphic function (single complex variable).06.01.??Cauchy-Riemann equations + complex differentiability.06.02.??Cauchy integral theorem + formula.06.02.??Residue theorem.06.03.??Riemann surface — definitions, examples.06.03.??Sheaf of holomorphic functions.06.04.??Divisor on a Riemann surface.06.04.??Riemann-Roch theorem (for compact Riemann surfaces).06.05.??Jacobian variety + Abel-Jacobi map.06.05.??Theta function on a Riemann surface.06.06.??Uniformisation theorem (Riemann mapping + uniformisation).06.07.??Algebraic curve ↔ Riemann surface correspondence (link to Strand A).
Wave 2 supporting units (unique to RS)
- Power series in one complex variable
- Holomorphic vector bundle on a Riemann surface
- Meromorphic function
- Branch point / branched covering
- Genus of a Riemann surface
- Hyperelliptic curve
- Kähler form on a Riemann surface
- Hodge theory for compact Riemann surfaces
- Mittag-Leffler theorem
- Weierstrass preparation theorem
Foundations already shipped (reuse)
- Topological space, continuous map, metric space (for compactness)
- Smooth manifold (Riemann surfaces are 2-real-dim with extra structure)
- Differential forms, de Rham cohomology
- Covering space, double cover
- Lie group ( via Möbius transformations)
Estimated breakdown
- Apex: 12 units
- New supporting: ~10 units
- Total new production: ~22 units
Owner: claude (one of three claude strands)
5. Strand D — Representation theory
Apex synthesis: Cartan-Weyl classification of finite-dimensional Lie algebra reps, Peter-Weyl theorem, Borel-Weil-Bott.
Apex units (Wave 1 equivalent)
07.01.??Group representation (general).07.01.??Schur's lemma.07.02.??Character of a finite-group representation.07.02.??Character orthogonality + decomposition.07.03.??Highest weight representation of a complex semisimple Lie algebra.07.03.??Weight lattice + root system + Weyl group.07.04.??Cartan-Weyl classification of finite-dim irreducible reps.07.05.??Compact Lie group + maximal torus.07.05.??Peter-Weyl theorem.07.06.??Flag variety.07.06.??Borel-Weil-Bott theorem.07.07.??Connection to physics: , in particle physics.
Wave 2 supporting units (unique to RT)
- Symmetric group representation
- Young tableau + Young symmetriser
- Cartan subalgebra + root space decomposition
- Verma module + highest-weight construction
- Universal enveloping algebra
- Casimir element
- Weyl character formula
- Killing form (already in Lie algebra unit, refine here)
- Schur-Weyl duality
- Bruhat decomposition / parabolic subgroup
Foundations already shipped (reuse)
- Group, group action, Lie group, Lie algebra
- Vector space, bilinear form
- Compact (topology), Hilbert space (for Peter-Weyl on )
- Tensor product, tensor algebra
- Spin group (already shipped as concrete Lie group example)
Estimated breakdown
- Apex: 12 units
- New supporting: ~10 units
- Total new production: ~22 units
Owner: claude (one of three claude strands)
6. Strand E — Statistical field theory & lattice models
Apex synthesis: Onsager solution of 2D Ising, renormalisation group flow, universality classes for phase transitions.
Apex units (Wave 1 equivalent)
08.01.??Partition function (statistical mechanics).08.01.??Ising model (definition + ferromagnetic / antiferromagnetic phases).08.02.??Mean-field theory + Curie-Weiss.08.03.??Onsager solution of 2D Ising (transfer matrix).08.04.??Renormalisation group (real-space block decimation).08.04.??Wilson-Fisher fixed point + universality.08.05.??Critical exponents + scaling laws.08.06.??Gaussian field theory + free boson.08.06.??Conformal symmetry at criticality (link to existing CFT unit).08.07.??Path integral formulation of statistical mechanics.08.08.??Wilson's lattice formulation of gauge theory.08.09.??Quantum-classical correspondence (Wick rotation).
Wave 2 supporting units (unique to SFT)
- Boltzmann distribution + canonical ensemble
- Free energy + Helmholtz / Gibbs
- Correlation function (statistical mechanics)
- Transfer matrix (general)
- Spontaneous symmetry breaking
- Mermin-Wagner theorem
- Block-spin decimation
- Beta function (RG)
- Lattice gauge theory (Wilson action)
- Effective field theory
Foundations already shipped (reuse)
- Hilbert space (for path-integral Hilbert spaces)
- Lie algebra (for gauge symmetries)
- Differential forms (for action functionals)
- CFT basics (already shipped as Wave 1 apex)
- Tensor product
Estimated breakdown
- Apex: 12 units
- New supporting: ~10 units
- Total new production: ~22 units
Owner: gpt-codex (one of two gpt-codex strands)
7. Production division of labor
claude (3 strands): A. Algebraic geometry, C. Riemann surfaces & complex analysis, D. Representation theory.
These three strands are mathematically adjacent (commutative algebra + complex/algebraic geometry + Lie/rep theory) and lean heavily on prose-density material. They share substantial supporting infrastructure: schemes appear in AG and Riemann surfaces, Lie reps appear in Borel-Weil and connect to compact-Lie classifications.
gpt-codex (2 strands): B. Symplectic geometry, E. Statistical field theory & lattice models.
These two strands are physics-flavored, computational, and somewhat self-contained. Symplectic geometry leans on Lie group + diffgeo foundations; SFT leans on CFT + Hilbert space. The gpt-codex session has shown strong production speed on physics-style technical content (CFT basics, Yang-Mills, Bott periodicity).
Why this split
- Mathematical adjacency: claude's three strands form a connected sub-DAG (sheaf cohomology in AG ↔ holomorphic line bundles on Riemann surfaces ↔ characters of compact Lie groups → Borel-Weil). Producing them together lets cross-references resolve as production proceeds.
- Prose density: AG, RS, RT have heavy prose components (definitions of schemes, divisors, weight lattices). claude's Master-tier prose pace fits this.
- Computational density: SG and SFT have more action-functional / partition-function / commutator computation. gpt-codex has shown speed and accuracy on this style.
- Independence: SG and SFT can run completely independently of claude's three strands; collisions on shared files (
docs/catalogs/CONCEPT_CATALOG.md,manifests/deps.json,docs/pilot-lessons.md) are the only coordination point.
Estimated production time
Per strand: ~22 new units at the post-pilot scaffold cadence (~2–5 min per unit for the parallel session, ~15–30 min per unit for claude with full LM Master prose).
- claude's 3 strands: ~66 units. At ~20 min/unit average, ~22 hours of focused work, distributable across multiple sessions.
- gpt-codex's 2 strands: ~44 units. At ~5 min/unit, ~3.5 hours.
Realistic calendar: 2–3 weeks of intermittent work brings v0.5 to closure (with foundations already shipped, this is genuinely tractable).
8. Strand-batch files (paste-ready for gpt-codex)
The two gpt-codex strands need their own batch scaffolds. Written as separate files:
docs/batches/V05_GPT_BATCH_B_SYMPLECTIC.md— Strand B (Symplectic geometry) Wave 1 apex queue.docs/batches/V05_GPT_BATCH_E_SFT.md— Strand E (Statistical field theory) Wave 1 apex queue.
Each file contains:
- Read-first list (PILOT_PLAN, QUALITY_RUBRIC, etc.)
- Production queue (~10 apex units in dependency order)
- Per-unit production protocol
- Hard conventions and prose standard
- Stop conditions
The claude-side strands (A, C, D) are produced from docs/plans/CURRICULUM_V0_5_PLAN.md directly — claude reads the strand definition above and produces from it.
9. Numbering convention
Existing v0.x uses sections 00–03. v0.5 strands continue:
- 04 — Algebraic geometry (Strand A)
- 05 — Symplectic geometry (Strand B)
- 06 — Riemann surfaces & complex analysis (Strand C)
- 07 — Representation theory (Strand D)
- 08 — Statistical field theory & lattice models (Strand E)
Each strand has chapters 01–10 (subject to refinement during production). Apex units are roughly in the higher chapter numbers per strand; supporting units in lower numbers.
10. Success criteria (v0.5)
v0.5 succeeds if:
- All 5 strands ship at least 80% of their planned apex units (8 of ~10 each).
- Each strand's apex units have
pending_prereqs: false(every prereq resolves). -
validate_all.pyis green at unit count ≥ 200 (66 v0.x + ~135 v0.5). -
pnpm buildclean, all unit pages render. - Cross-strand cross-references work: a learner reading Strand A's Riemann-Roch can click through to Strand C's compact Riemann surface for the curve case.
- LM editorial review pass on each strand's Master tier catches no flagrant violations.
- No more than 2 units in the entire shipped DAG have
pending_prereqs: true.
v0.5 fails if:
- Any strand stalls below 50% apex completion.
- Cross-strand references break (e.g., AG references a Strand C unit that was never produced).
- The Master-prose drift reappears (suggesting the rubric needs further tightening).
- The validator fails on more than 5 units after a strand reports.
11. Exit conditions
After v0.5 closes:
- v1 launch readiness: rendering polish (KaTeX + theme + tier filter UX), exercise interactivity (interactive widgets — Neutron-side work), RAG layer over
reference/, reviewer attestation pass. - v0.6 lateral expansion: 2–3 more strands beyond the v0.5 five (geometric quantization, number theory, advanced algebraic topology, etc.) — the same scaffold-driven pattern repeated.
- Consolidation: rubric evolution (v3 of docs/specs/QUALITY_RUBRIC.md); LM-editorial-writer agent review on all v0.5 Master prose; sourcing-acquisition pass to resolve TODO_REF placeholders.
The v0.5 plan's purpose is twofold: (1) bring Codex to Fast Track parity in modern-geometry breadth, (2) prove the lateral-expansion model works at scale.
v0.5 Lateral Expansion Plan drafted 2026-04-28 immediately after Wave 5 closure. 5 strands, 2-session production split, ~145 new units, 2–3 week target window.