← all sources

Kobayashi-Nomizu — *Foundations of Differential Geometry, Vol. II* (Fast Track 3.19) — Audit + Gap Plan

Book: Shoshichi Kobayashi, Katsumi Nomizu, Foundations of Differential Geometry, Volume II. Interscience Tracts in Pure and Applied Mathematics 15, Interscience Publishers (Wiley), 1969. xv + 470 pp. Reprinted Wiley Classics Library 1996 (ISBN 0-471-15732-5). The canonical English-language reference for complex / Hermitian / Kähler differential geometry and for the Chern-Weil construction of characteristic classes via curvature of connections on principal bundles.

Fast Track entry: 3.19. Sibling to KN-I (FT 3.18, audit shipped this Cycle 4 — see plans/fasttrack/kobayashi-nomizu-foundations-vol1.md). KN-II picks up where KN-I leaves off and assumes the entire Vol. I apparatus (principal bundles, connections, curvature, holonomy, Cartan structural equations) as prerequisite. The two volumes are routinely cited together as "KN-I + KN-II"; the Codex Fast Track lists them as separate entries because the audit + production effort is substantively distinct.

Purpose of this plan: lightweight audit-and-gap pass (P1-lite + P2 + P3-lite of the orchestration protocol). Output is a concrete punch-list of new units so that Foundations of Differential Geometry Vol. II (KN-II hereafter) is covered to the equivalence threshold (≥95% effective coverage of theorems, key examples, exercise pack, notation, sequencing, intuition, applications — see docs/plans/FASTTRACK_EQUIVALENCE_PLAN.md §3.4).

Audit mode: REDUCED. No local PDF is available (reference/textbooks-extra/ and reference/fasttrack-texts/03-modern-geometry/ checked — only the KN-I cover-image stub reference/fast-track/images/Kobayashi-Nomizu-1-683x1024__72960fe9e3.jpg is present; KN-II is under active Wiley copyright and was not retrieved within the time budget). This pass works from the canonical KN-II table of contents (Chs. VIII–XII + appendices, well-attested across the modern complex-geometry literature), the peer-source crosswalks below (Wells, Huybrechts, Voisin, Tu, Milnor-Stasheff), the Fast Track entry's editorial framing, the in-Codex evidence that KN-II is already cited as the master anchor for 03.06.06-chern-weil-homomorphism.md (via Kobayashi-Nomizu Vol. II Ch. XII), and the sibling KN-I audit's findings. A full P1 line-number inventory is deferred to the production pass when a local copy is on disk.


§1 What KN-II is for

KN-II is the canonical reference for the complex-and-curvature half of differential geometry. Where KN-I organises connections on principal -bundles, parallel transport, the Cartan structural equations, and the holonomy programme over real manifolds with structure group or , KN-II makes two pivotal moves: (i) it pushes the connection-and-curvature calculus through to complex / almost-complex manifolds, Hermitian and Kähler manifolds, and homogeneous spaces, and (ii) it culminates in Chapter XII with the Chern-Weil homomorphism, the curvature-based geometric definition of characteristic classes that competes head-on with the homotopy-theoretic definition (Milnor-Stasheff, classifying spaces) and provides the bridge between Vol. I's connection theory and modern index theory / gauge theory [ref: L. Tu, Differential Geometry: Connections, Curvature, and Characteristic Classes (Graduate Texts in Mathematics 275, Springer 2017) Preface ("written to bridge Kobayashi-Nomizu Vol. I §III + Vol. II §XII into modern notation") and Chapters 22–25].

Distinctive content, organised by the five chapters of the volume:

  1. Chapter VIII — Submanifolds. Second fundamental form $\mathrm{II}(X, Y) = (\nabla_X Y)^\perpf: M \hookrightarrow \bar M$; the Gauss, Codazzi, and Ricci equations that relate the intrinsic curvature of to the curvature of and the second fundamental form. Totally geodesic submanifolds, minimal submanifolds (mean curvature zero), and totally umbilical submanifolds. KN-II §VIII.1–§VIII.5. The chapter is the canonical reference for the submanifold-theoretic side of Riemannian geometry; compare do Carmo Riemannian Geometry Ch. 6 and Spivak Comprehensive Introduction Vol. III Chs. 1–4 [ref: M. P. do Carmo, Riemannian Geometry (Birkhäuser 1992) Ch. 6; M. Spivak, A Comprehensive Introduction to Differential Geometry Vol. III (Publish or Perish 3rd ed. 1999) Chs. 1–4].
  2. Chapter IX — Complex and almost-complex manifolds. Almost-complex structure with ; type decomposition ; Nijenhuis tensor . The Newlander-Nirenberg integrability theorem (1957): comes from a complex-manifold structure iff . Complex vector bundles and the canonical decomposition $\Omega^k(M; \mathbb{C}) = \bigoplus_{p+q=k} \Omega^{p,q}(M)\partial\bar\partial$, and the Dolbeault complex. Hermitian metrics on complex vector bundles and on . The Chern connection on a holomorphic Hermitian vector bundle: the unique connection compatible with both the holomorphic structure and the Hermitian metric. KN-II §IX.1–§IX.9. Compare Wells Differential Analysis on Complex Manifolds Chs. I–III and Huybrechts Complex Geometry Ch. 2 [ref: R. O. Wells, Differential Analysis on Complex Manifolds (Graduate Texts in Mathematics 65, Springer 3rd ed. 2008, with new appendix by O. García-Prada) Chs. I–III; D. Huybrechts, Complex Geometry: An Introduction (Universitext, Springer 2005) Ch. 2].
  3. Chapter IX continued — Kähler manifolds. A Hermitian manifold is Kähler iff the Kähler form $\omega = g(J\cdot, \cdot) \in \Omega^{1,1}(M)\nabla J = 0$, equivalently iff the Chern connection equals the Levi-Civita connection. Kähler identities , ; the Hodge decomposition on compact Kähler manifolds $H^k(M; \mathbb{C}) = \bigoplus_{p+q=k} H^{p,q}(M)H^{p,q} = \overline{H^{q,p}}\partial\bar\partial$-lemma**; hard Lefschetz . KN-II §IX.7–§IX.9 sketches these; the deep proofs are deferred to the Hodge-theoretic literature [ref: C. Voisin, Hodge Theory and Complex Algebraic Geometry I (Cambridge Studies in Advanced Mathematics 76, CUP 2002) Chs. 6–8 — the canonical modern treatment of Kähler-Hodge theory; D. Huybrechts, Complex Geometry §3.2–§3.3]. Originator-paper citation: K. Kodaira, "On Kähler varieties of restricted type," Annals of Math. 60 (1954) 28–48 — the foundational paper establishing the Kodaira embedding and projective-embedding criterion for compact Kähler manifolds.
  4. Chapter X — Homogeneous spaces. A homogeneous space is a quotient for a Lie group and closed subgroup ; KN-II develops the theory of invariant connections on , the canonical connection on a reductive homogeneous space (where $\mathfrak{g} = \mathfrak{h} \oplus \mathfrak{m}\mathrm{Ad}(H)\mathfrak{m} \subseteq \mathfrak{m}$), the Nomizu construction of -invariant affine connections, and the specialisation to symmetric spaces (where in addition $[\mathfrak{m}, \mathfrak{m}] \subseteq \mathfrak{h}$). The Cartan classification of irreducible Riemannian symmetric spaces is stated and referenced; the proof is deferred to Helgason Differential Geometry, Lie Groups, and Symmetric Spaces. KN-II §X.1–§X.6. Compare Helgason Chs. IV–VIII [ref: S. Helgason, Differential Geometry, Lie Groups, and Symmetric Spaces (Graduate Studies in Mathematics 34, AMS 2001) Chs. IV–VIII].
  5. Chapter XI — Transformations of complex / Hermitian / Kähler manifolds. Holomorphic transformations, infinitesimal holomorphic transformations (holomorphic vector fields with ), isometries of Hermitian and Kähler manifolds, and the Bochner technique (using Weitzenböck-style curvature identities to obtain vanishing theorems for Killing fields and harmonic forms on manifolds with positive curvature). KN-II §XI.1–§XI.5.
  6. Chapter XII — Characteristic classes (the Chern-Weil construction). The technical and conceptual climax of the volume. For a principal -bundle with connection and curvature , the Chern-Weil homomorphism is the map from the algebra of -invariant polynomials on to de Rham cohomology, sending an invariant polynomial of degree to the cohomology class of . Chern classes for complex vector bundles, Pontryagin classes , the Euler class from the Pfaffian, the Todd class, the -class, the -class. The transgression formula computing the cohomology class of via a Chern-Simons form. Independence of connection (the central theorem). The bridge to Milnor-Stasheff's homotopy-theoretic definition (via classifying spaces) is stated but proved only as compatibility of the two definitions. KN-II §XII.1–§XII.5. Compare Milnor-Stasheff Appendix C and Tu Chs. 22–25 [ref: J. Milnor, J. Stasheff, Characteristic Classes (Annals of Math. Studies 76, Princeton University Press 1974) Appendix C — the canonical statement of the Chern-Weil construction in the topology-textbook tradition; L. Tu, Differential Geometry: Connections, Curvature, and Characteristic Classes (GTM 275, Springer 2017) Chs. 22–25 — the modern teaching version of KN-II §XII]. Originator-paper citations: S.-S. Chern, "Characteristic classes of Hermitian manifolds," Annals of Math. 47 (1946) 85–121 — the originating paper for the curvature construction of complex characteristic classes; A. Weil, unpublished lecture notes 1949 (circulated as a mimeograph; later collected in Œuvres scientifiques), which extended Chern's curvature recipe to all principal -bundles via invariant polynomials — this is the work that the Codex unit 03.06.06-chern-weil-homomorphism.md is named after.
  7. Editorial signature. KN-II is uncompromisingly bundle-and-curvature first in the same spirit as KN-I. Complex manifolds are introduced via the almost-complex / integrability route (not via local holomorphic coordinates as in a complex-analysis text); Kähler manifolds are identified by the Kähler condition after the almost- complex / Chern-connection apparatus is in place; characteristic classes are built from curvature after the full Vol. I + Vol. II §IX curvature calculus is available. This is the opposite order from Wells (which starts from sheaf cohomology and local Dolbeault) and Huybrechts (which starts from local complex geometry); it is the same order as Voisin (which also runs Hodge theory through the curvature-and-connection route) and Tu (which is explicitly a teaching rewrite of KN-II §XII). The principal-bundle-first ordering is what makes KN-II the natural bridge to gauge theory (Yang-Mills measures the curvature norm of a connection on a Hermitian or unitary bundle) and index theory (Atiyah-Singer expresses the index of an elliptic operator as the pairing of characteristic classes against the fundamental class) [ref: Tu Preface; D. Salamon, Spin Geometry and Seiberg-Witten Invariants (preprint, ETH Zürich 2000) §1 — both citing KN-II §XII as the canonical bridge between connection theory and characteristic classes].
  8. Peer-source contrast vs Milnor-Stasheff. KN-II §XII and Milnor-Stasheff give two different definitions of characteristic classes that coincide in their cohomological output: KN-II builds $c_i \in H^{2i}{\mathrm{dR}} (M; \mathbb{R})$ from the curvature of any connection on a complex vector bundle (the differential-geometric definition); Milnor-Stasheff builds axiomatically and via the classifying-map construction (the homotopy-theoretic / topological definition). The two agree under the de Rham comparison $H^(M; \mathbb{Z}) \otimes \mathbb{R} \cong H^{\mathrm{dR}}(M; \mathbb{R})$ for the Chern classes valued in but disagree on torsion (Stiefel-Whitney classes, the integral lift of Chern classes), which is why both viewpoints are needed [ref: Milnor-Stasheff Appendix C; Voisin §11 — the explicit compatibility statement; Bott-Tu §20–§23 — runs both constructions and shows compatibility].

KN-II is not a first textbook on complex manifolds (Wells / Huybrechts serve that role at a more accessible pace) and not a first textbook on characteristic classes (Milnor-Stasheff serves that role with simpler axiomatic foundations). The canonical "before KN-II" sequence is KN-I → Wells → KN-II, or KN-I → Huybrechts → KN-II. The canonical "after KN-II" sequence is KN-II → Voisin (deep Hodge theory) → Donaldson-Kronheimer (four-manifold gauge theory) → Joyce (special holonomy / Calabi-Yau).


§2 Coverage table (Codex vs KN-II)

Cross-referenced against the current Codex corpus. ✓ = covered, △ = partial / different framing, ✗ = not covered. KN-II material maps primarily to 03-modern-geometry/02-manifolds/, 03-modern-geometry/05-bundles/, 03-modern-geometry/06-characteristic-classes/, the 05-symplectic/almost-complex/ chapter, the 04-algebraic-geometry/09-hodge/ chapter, and adjacent.

KN-II topic Codex unit(s) Status Note
Ch. VIII — submanifolds
Isometric immersion, second fundamental form Gap. No anchor unit. Cited downstream (e.g. in 05-symplectic/lagrangian/ Lagrangian-submanifold framing) without a definitional unit.
Gauss equation Gap. Foundational; standard prereq for Riemannian comparison geometry.
Codazzi-Mainardi equation Gap.
Ricci equation (normal-bundle curvature) Gap.
Totally geodesic / minimal / totally umbilical submanifolds Gap. Cited informally in symplectic units (Lagrangian = totally null + half-dim) without an anchor.
Ch. IX — complex and almost-complex manifolds
Almost-complex structure , 05.06.01-almost-complex.md Shipped in the symplectic chapter (not the manifolds chapter), framed as "almost-complex structure on a symplectic manifold". KN-II frames as a manifold-level structure independent of any symplectic form; the Codex framing is narrower.
Nijenhuis tensor △ (inside 05.06.03) Mentioned in 05.06.03-newlander-nirenberg.md as the integrability obstruction. No dedicated unit; not anchored to a manifold-level .
Type decomposition Gap. Foundational; not anchored as its own unit.
Newlander-Nirenberg integrability theorem 05.06.03-newlander-nirenberg.md Shipped; master anchor Newlander-Nirenberg 1957, Hörmander, Huybrechts, Voisin. Good coverage.
Dolbeault complex Gap. Cited in 05.06.03 Master tier without an anchor unit.
Dolbeault cohomology Gap. Load-bearing for Hodge theory and Kodaira-vanishing.
Complex vector bundle 03.05.08-complex-vector-bundle.md Shipped.
Holomorphic vector bundle (definition, transition functions) Gap. Distinct from smooth complex bundle. Cited in 04.09.02-kodaira-vanishing.md without an anchor.
Hermitian metric on a complex vector bundle Gap.
Chern connection (unique compatible connection on a holomorphic Hermitian bundle) Gap. Distinctive to complex differential geometry; load-bearing for the Chern-class curvature formula.
Ch. IX — Kähler manifolds
Hermitian metric on a complex manifold Gap.
Kähler form ; Kähler condition Gap. Standard reference for the entire Kähler-Hodge-theoretic literature.
Equivalence: Chern = Levi-Civita Gap. The defining theorem of Kähler geometry.
Kähler identities etc. Gap.
Hodge decomposition for compact Kähler manifolds 04.09.01-hodge-decomposition.md A hodge-decomposition unit ships in 04-algebraic-geometry/09-hodge/; it covers the algebraic-geometric framing but may not give the KN-II Kähler-manifold proof. To verify in the production pass.
Kodaira vanishing theorem 04.09.02-kodaira-vanishing.md Shipped in algebraic geometry chapter; master anchor Kodaira 1954.
-lemma Gap. Load-bearing for formality of compact Kähler manifolds.
Hard Lefschetz Gap.
Ch. X — homogeneous spaces
Homogeneous space Touched in 03-modern-geometry/03-lie/ (Lie-group chapter) and in 05-symplectic/coadjoint/ (coadjoint orbits as ). No dedicated "homogeneous-space" unit at manifold level.
Reductive decomposition Gap. Foundational for invariant-connection theory.
Canonical connection on a reductive homogeneous space Gap. Distinctive to KN-II §X.
Nomizu construction (invariant affine connections) Gap.
Symmetric space (Lie-triple condition ) Gap. Cited via coadjoint and 03.09.18-berger-holonomy.md (Berger's list includes symmetric spaces) without an anchor.
Cartan classification of irreducible Riemannian symmetric spaces Gap. Referenced from 03.09.18.
Ch. XI — transformations
Holomorphic transformation, infinitesimal holomorphic vector field Gap.
Isometries of Hermitian / Kähler manifolds Gap.
Bochner technique (vanishing theorems via curvature) Gap. Load-bearing for Bonnet-Myers-style results in Kähler setting.
Ch. XII — characteristic classes via Chern-Weil
Invariant polynomial 03.06.05-invariant-polynomial.md Shipped.
Chern-Weil homomorphism 03.06.06-chern-weil-homomorphism.md Shipped; master anchor "Kobayashi-Nomizu Vol. II Ch. XII". The unit's references block has a source: TODO_REF for the KN-II citation — the production pass should resolve it.
Independence-of-connection theorem △ (inside 03.06.06) Stated in 03.06.06 Master tier; proof is sketched but not at line-number granularity.
Chern classes via curvature 03.06.04-pontryagin-chern-classes.md Shipped axiomatically + with worked example; the explicit curvature formula is in 03.06.06 Master tier but not as a standalone unit.
Pontryagin classes via curvature 03.06.04-pontryagin-chern-classes.md Same as above — axiomatic + reference to Chern-Weil construction; the curvature formula is partial.
Euler class via the Pfaffian of curvature Pfaffian computation is referenced in 03.06.06 Master tier but no dedicated unit. The de Rham Euler class is in 03.04.09-thom-global-angular-form.md via the Thom form.
Chern-Simons transgression form Gap. Distinctive to KN-II §XII.4 (and a load-bearing concept for gauge theory and TQFT). Referenced informally in 03.07.05-yang-mills-action.md (Chern-Simons action) without a curvature-side anchor.
Todd class, -class, -class via curvature appears in 03.09.10 (Atiyah-Singer), in 03.06.04; the Chern-Weil curvature formulas are partial.
Compatibility of Chern-Weil and Milnor-Stasheff definitions (de Rham comparison) Gap. The unit 03.06.06 references both; the explicit statement and proof of compatibility is not anchored.
Appendices
Integration on complex manifolds (real and complex orientation) Touched implicitly; KN-II Appendix material is short.

Aggregate coverage estimate: ~25–30% of KN-II has corresponding Codex units. Chapter XII (Chern-Weil) is the best-covered chapter at ~60% because 03.06.05 + 03.06.06 + 03.06.04 form the Chern-Weil spine and the Milnor-Stasheff audit has already flagged the remaining gaps. Chapter IX (complex / almost-complex / Kähler) is ~15% covered: Newlander-Nirenberg ships, the almost-complex structure ships (with a symplectic framing), but holomorphic bundles, Chern connection, Hermitian metric, Kähler form, Kähler identities, -lemma, and hard Lefschetz are all gaps. Chapter VIII (submanifolds) is ~0% covered: no Gauss-Codazzi-Ricci equations, no second fundamental form. Chapter X (homogeneous spaces) is ~5% covered: touched in Lie-group and coadjoint chapters but no canonical-connection unit. Chapter XI (transformations) is ~0% covered: no Bochner technique, no Kähler-isometry framework.

Silent KN-II dependencies in the Codex. The audit reveals a cluster of units that cite KN-II as their master anchor (directly or implicitly) but whose load-bearing prerequisites are uncovered:

  1. 03.06.06-chern-weil-homomorphism.md (master = "Kobayashi-Nomizu Vol. II Ch. XII; Milnor-Stasheff Appendix C") — source: TODO_REF for the KN-II citation. Silently depends on a missing Chern connection unit (for the complex-bundle special case) and on the missing transgression / Chern-Simons machinery.
  2. 04.09.01-hodge-decomposition.md — covers the algebraic-geometric framing of Hodge decomposition; the KN-II Kähler-manifold proof via Kähler identities is the load-bearing differential-geometric route and has no anchor in the Codex.
  3. 04.09.02-kodaira-vanishing.md — cites Kodaira 1954 directly; the prerequisite holomorphic bundle and Hermitian metric / Chern connection layer is missing.
  4. 05.06.01-almost-complex.md — frames as a structure on a symplectic manifold; the KN-II manifold-level framing (independent of any symplectic form) is the wider concept.
  5. 05.06.03-newlander-nirenberg.md — cites Voisin and Huybrechts; the prerequisite type decomposition and Dolbeault complex are not anchored.
  6. 03.09.18-berger-holonomy.md — Berger's list includes Kähler () and Calabi-Yau () holonomy; the prerequisite Kähler-manifold and Calabi-Yau definitions are not anchored.
  7. 03.07.05-yang-mills-action.md — Yang-Mills lives on a Hermitian bundle with a -connection; the prerequisite Hermitian bundle and Chern connection layer overlaps with the gaps above.

Net effect: the existing Codex 06-characteristic-classes/ chapter cites KN-II as its canonical reference and covers ~60% of the relevant material; the 02-manifolds/ chapter covers ~10% of the complex / Kähler prerequisite layer; the 04-algebraic-geometry/09-hodge/ chapter covers the Hodge / Kodaira downstream at ~70% via algebraic-geometric framing but with the differential-geometric KN-II proof route absent. The KN-II audit is therefore load-bearing across four chapters: 02-manifolds/, 05-bundles/, 06-characteristic-classes/, and 04.09-hodge/.


§3 Gap punch-list (P3-lite — units to write, priority-ordered)

Priority 0 — prerequisite chain shared with KN-I and Milnor-Stasheff audits:

These are listed here because KN-II assumes them; they are already on the KN-I punch-list (FT 3.18) and / or the Milnor-Stasheff punch-list (FT 3.08). Ship once, cite from both.

  • 03.05.14 Torsion tensor and the two Cartan structural equations (KN-I punch-list, priority 1) — load-bearing for KN-II §IX (Chern connection is the unique connection with on a holomorphic Hermitian bundle).
  • 03.03.X1 Levi-Civita connection, geodesics, exp, Hopf-Rinow (KN-I punch-list, priority 1) — load-bearing for KN-II §VIII (submanifold geometry) and §IX (Kähler ⇔ Chern = Levi-Civita).
  • 03.05.13 Associated bundle and induced connection (KN-I punch-list, priority 1) — load-bearing for KN-II §XII (curvature of an associated vector bundle is what enters Chern-Weil).

Priority 1 — Ch. IX core (complex / almost-complex / Hermitian / Kähler):

  1. 03.02.09 Almost-complex structure (manifold-level). with ; type decomposition $TM \otimes \mathbb{C} = T^{1,0}M \oplus T^{0,1}MN_J(X, Y)$. Sits in 02-manifolds/ (per the KN-I audit, this chapter is wide open). This is a manifold-level lift of the existing 05.06.01-almost-complex.md (which lives in the symplectic chapter and uses the symplectic framing). Cross-reference both. KN-II §IX.1–§IX.2 anchor; Wells §I.1 + Huybrechts §2.6 secondary. ~1500 words. Three-tier.
  2. 03.02.10 Complex manifold and the Dolbeault complex. Holomorphic atlas; as smooth -forms; the operators $\partial, \bar\partial\bar\partial^2 = 0$; the Dolbeault complex and Dolbeault cohomology . KN-II §IX.2–§IX.3 anchor; Wells Ch. II + Huybrechts §2.6 secondary. ~1800 words. Three-tier.
  3. 03.05.19 Holomorphic vector bundle. Definition (transition functions holomorphic), Dolbeault on , the Koszul-Malgrange theorem that holomorphic structures on a smooth complex bundle ↔ flat -operators. KN-II §IX.4 anchor; Wells §III.1 secondary; Huybrechts §2.6 secondary. ~1500 words. Three-tier. Closes the silent gap behind 04.09.02-kodaira-vanishing.md.
  4. 03.05.20 Hermitian metric on a complex bundle; Chern connection. Hermitian metric on a complex bundle ; the unique connection compatible with both the holomorphic structure and the Hermitian metric (the Chern connection). Formula in local holomorphic frame: . KN-II §IX.5 anchor; Wells §III.2; Huybrechts §4.2 secondary. ~1500 words. Three-tier. Closes the silent gap behind 03.06.06-chern-weil-homomorphism.md for the complex-bundle special case.
  5. 03.02.11 Hermitian manifold and the Kähler form. Hermitian metric on with ; the Kähler form $\omega \in \Omega^{1,1}(M)\omega(X, Y) = g(JX, Y)$; Kähler condition . The equivalence theorem: $d\omega = 0 \Leftrightarrow \nabla J = 0 \LeftrightarrowTM$ equals the Levi-Civita connection. KN-II §IX.6–§IX.7 anchor; Huybrechts §3.1 secondary; Voisin §3.1 secondary. ~2000 words. Three-tier. Master tier of any Hodge-theoretic unit downstream depends on this.
  6. 03.02.12 Kähler identities and the Hodge decomposition (Kähler version). The Kähler identities , ; the consequence that on a compact Kähler manifold; the Hodge decomposition with $H^{p,q} = \overline{H^{q,p}}$. KN-II §IX.7 anchor; Voisin §6 secondary; Huybrechts §3.2 secondary. ~2000 words. Master-tier dominant; Intermediate gives the statement of Hodge decomposition only. Sharpens 04.09.01-hodge-decomposition.md with the differential-geometric proof route.

Priority 2 — Ch. XII Chern-Weil deepenings + Ch. VIII submanifolds:

  1. 03.06.07 Chern-Simons / transgression form. For a connection on a principal -bundle with curvature , the transgression form with for an invariant polynomial of degree . The Chern-Simons 3-form $CS(\omega) = \mathrm{tr}(\omega \wedge d\omega + \tfrac{2}{3} \omega \wedge \omega \wedge \omega)$ as the canonical transgression of the second Chern class. KN-II §XII.4 anchor; Chern-Simons 1974 originator citation. ~1500 words. Master-tier dominant. Bridges 03.06.06-chern-weil-homomorphism.md to 03.07.05-yang-mills-action.md (Chern-Simons action) and to topological field theory.
  2. 03.06.18 Compatibility of Chern-Weil and Milnor-Stasheff Chern classes. The de Rham comparison: the curvature class equals the image of the topological under . Generalisation to all Chern classes. KN-II §XII.5 anchor; Milnor-Stasheff Appendix C secondary. ~1500 words. Master-tier dominant. Shared with the Milnor-Stasheff punch-list (FT 3.08, priority-3); ship once and cite from both audits.
  3. 03.02.13 Isometric immersion and the second fundamental form. Isometric immersion of Riemannian manifolds; the second fundamental form ; the mean curvature vector . KN-II §VIII.1 anchor; do Carmo Ch. 6 secondary. ~1500 words. Three-tier.
  4. 03.02.14 Gauss, Codazzi, and Ricci equations. The three structure equations relating the curvature of , the curvature of , and the second fundamental form. Worked example: $S^n \subseteq \mathbb{R}^{n+1}$ with the standard immersion. KN-II §VIII.2–§VIII.4 anchor; do Carmo Ch. 6 secondary. ~2000 words. Three-tier.

Priority 3 — Ch. X homogeneous spaces + Ch. XI transformations:

  1. 03.03.X2 Homogeneous space and reductive decomposition. Quotient manifold structure on for a Lie group and a closed subgroup; reductive decomposition $\mathfrak{g} = \mathfrak{h} \oplus \mathfrak{m}\mathrm{Ad}(H)\mathfrak{m} \subseteq \mathfrak{m}$. KN-II §X.1–§X.2 anchor; Helgason Ch. IV secondary. ~1500 words. Three-tier. Sits in the 03-lie/ chapter; lateral connection to 05-symplectic/coadjoint/ (coadjoint orbits as homogeneous spaces).
  2. 03.03.X3 Canonical connection on a reductive homogeneous space; symmetric space. The Nomizu construction of -invariant affine connections; the canonical connection (corresponding to - invariant bilinear form on ); specialisation to symmetric spaces (). Pointer to the Cartan classification of irreducible Riemannian symmetric spaces (statement only). KN-II §X.2–§X.6 anchor; Helgason Chs. IV, VIII secondary. ~1800 words. Master-tier dominant.
  3. 03.02.15 Bochner technique and curvature vanishing theorems. Weitzenböck formula on a Riemannian manifold; vanishing of harmonic forms and Killing fields under curvature-positivity assumptions; the Kähler-manifold specialisation (vanishing of on a manifold with positive Ricci form). KN-II §XI.4–§XI.5 anchor; Lawson-Michelsohn §II.8 secondary. ~1500 words. Master-tier dominant.

Priority 4 — survey pointers (Master-only, weaving edits):

  1. Pointer in 03.06.06-chern-weil-homomorphism.md to the new 03.05.20 (Chern connection) and 03.06.07 (Chern-Simons) units, and resolve the source: TODO_REF to KN-II §XII with concrete section locators. Single-paragraph weaving edit; resolves the audit-flagged TODO_REF.
  2. Pointer in 04.09.01-hodge-decomposition.md to the new 03.02.12 (Kähler identities + Kähler Hodge decomposition) as the differential-geometric route to the same theorem. Single-paragraph weaving edit.
  3. Pointer in 04.09.02-kodaira-vanishing.md to the new 03.05.19 (holomorphic bundle) and 03.05.20 (Hermitian metric / Chern connection) as the prerequisite layer.
  4. Pointer in 05.06.01-almost-complex.md to the new 03.02.09 (manifold-level almost-complex structure) as the upstream generic framing; the symplectic specialisation in 05.06.01 becomes a canonical example of the generic concept.
  5. Pointer in 05.06.03-newlander-nirenberg.md to 03.02.09 and 03.02.10 (Dolbeault complex) as the prerequisite layer; resolve the TODO_REF blocks accordingly.
  6. Pointer in 03.09.18-berger-holonomy.md to 03.02.11 (Kähler manifold) for the holonomy case and a forward pointer to the (deferred) Calabi-Yau unit for .
  7. Pointer in 03.07.05-yang-mills-action.md to 03.06.07 (Chern-Simons) for the Chern-Simons action specialisation.

§4 Implementation sketch (P3 → P4)

For a full KN-II coverage pass, priority-0 + priority-1 are the minimum set and close the complex-and-Chern-Weil silent-dependency gaps across four chapters. Realistic production estimate (mirroring earlier Brown / Bott-Tu / Milnor / KN-I batches):

  • ~3.5 hours per unit. KN-II units skew slightly above the corpus average (and the KN-I average) because the Master tier requires careful juggling of (i) the principal-bundle calculus from Vol. I, (ii) the complex-bundle / holomorphic / Hermitian layer, and (iii) the curvature-formula bookkeeping (Pfaffians, determinants of ).
  • Priority 0: 3 units shared with the KN-I + Milnor-Stasheff punch-lists (do not double-count); flagged here for prerequisite tracking only.
  • Priority 1: 6 units × ~3.5 hours = ~21 hours. Heart of the audit; closes the complex / Kähler gap in one batch and supplies prerequisites for the Hodge chapter and the Chern-Weil unit.
  • Priority 2: 4 units × ~3.5 hours = ~14 hours. Closes the Chern-Simons / transgression gap, the de Rham–topological compatibility gap, and the submanifold-equations gap (Ch. VIII).
  • Priority 3: 3 units × ~3 hours = ~9 hours. Closes Ch. X (homogeneous spaces) and Ch. XI (Bochner technique).
  • Priority 4: 7 weaving edits × ~30 min = ~3.5 hours.
  • Total for full coverage: ~47–48 hours, roughly a focused 7–10 day window. Priority-0 (carried by other audits) + priority-1 alone is ~21 hours and closes the load-bearing complex / Kähler gaps; with priority-2 (~14 hours more) the Chern-Weil chapter reaches FT-equivalence.

Originator-prose targets. Per docs/plans/FASTTRACK_EQUIVALENCE_PLAN.md §10, the following units should carry originator-prose citations:

  • S.-S. Chern, "Characteristic classes of Hermitian manifolds," Annals of Math. 47 (1946) 85–121 — the originating paper for the curvature construction of complex characteristic classes. Cite in 03.06.06 (audit-flagged TODO_REF resolution) and in 03.05.20 (Chern connection — historically derived from this paper).
  • André Weil, unpublished 1949 lecture notes (mimeograph; later in Œuvres scientifiques Vol. III) — generalised Chern's curvature recipe to all principal -bundles via invariant polynomials. Cite in 03.06.06 as the second half of the "Chern-Weil" name.
  • A. Newlander, L. Nirenberg, "Complex analytic coordinates in almost complex manifolds," Annals of Math. 65 (1957) 391–404 — the integrability theorem. Already cited in 05.06.03 (TODO_REF block); resolve concretely during the production pass and cross-cite in 03.02.09 (manifold-level almost-complex structure).
  • K. Kodaira, "On Kähler varieties of restricted type," Annals of Math. 60 (1954) 28–48 — the foundational paper for the compact-Kähler- manifold programme (Kodaira embedding, projectivity criterion). Cite in 03.02.11 (Kähler manifolds) and in 04.09.02 (Kodaira vanishing — already cited there).
  • S.-S. Chern, J. Simons, "Characteristic forms and geometric invariants," Annals of Math. 99 (1974) 48–69 — the originating paper for the Chern-Simons transgression form. Cite in 03.06.07.
  • W. V. D. Hodge, The Theory and Applications of Harmonic Integrals (Cambridge University Press 1941, 2nd ed. 1952) — originating the Hodge decomposition. Cite in 03.02.12.
  • K. Nomizu, "Invariant affine connections on homogeneous spaces," Amer. J. Math. 76 (1954) 33–65 — the Nomizu construction. Cite in 03.03.X3.
  • S. Bochner, "Vector fields and Ricci curvature," Bull. AMS 52 (1946) 776–797 — the Bochner technique. Cite in 03.02.15.
  • Kobayashi, Nomizu (1969) — the canonical consolidation. Cite throughout as the in-Codex master anchor.

Notation crosswalk. KN-II writes:

  • for the almost-complex structure; for the Nijenhuis tensor.
  • and for the type- and type- subbundles of .
  • for the smooth -forms.
  • for the Dolbeault operators; for Dolbeault cohomology.
  • for a Hermitian metric on a complex vector bundle; for the Chern connection.
  • for the Kähler form (reused from KN-I where is the connection 1-form — notation clash to flag in the Codex; resolve by writing for the Kähler form when in the same paragraph as the connection 1-form, or by using for the latter, as Tu does).
  • for the algebra of -invariant polynomials on .
  • for the Chern-Weil homomorphism.
  • for the characteristic classes (same as Milnor-Stasheff and Codex existing convention).

Wells, Huybrechts, and Voisin use the same complex-geometry notation. Tu uses identical notation to KN-II in the bundle / curvature register; Tu adopts the , aliases to bridge to the gauge-theory notation in 03.07.05-yang-mills-action.md (already recorded in the KN-I plan §4). The Codex notation decision (per docs/specs/UNIT_SPEC.md §11) should: adopt KN-II's complex-geometry notation verbatim; resolve the notation clash by reserving for the Kähler form inside the complex / Kähler units (03.02.11, 03.02.12) and writing in those units when the principal-bundle connection 1-form appears explicitly. Record in a §Notation paragraph of each affected unit.


§5 What this plan does NOT cover

  • A line-number-level inventory of every named theorem in KN-II (full P1 audit). Deferred until a local PDF is on disk in reference/fasttrack-texts/03-modern-geometry/Kobayashi-Nomizu-FoundationsVol2.pdf. This stub works from canonical TOC knowledge + peer-source crosswalks
    • Codex internal evidence and is therefore REDUCED.
  • The deep Hodge-theoretic programme (Lefschetz decomposition, primitive cohomology, polarised Hodge structures, mixed Hodge structures, period domains, period maps, the Calabi-Yau Theorem, the Hodge conjecture). Fast Track 3.27 — Voisin, Hodge Theory and Complex Algebraic Geometry I + II — is the canonical Codex audit target for that material. KN-II §IX only goes as far as Hodge decomposition on compact Kähler manifolds; everything downstream is Voisin territory and is deferred to its own audit.
  • Kähler-Einstein metrics and the Calabi-Yau theorem. KN-II does not cover Yau's solution of the Calabi conjecture. Deferred to a future Joyce / Tian audit pass (no current Fast Track entry).
  • Sasaki-Einstein and special holonomy beyond Kähler. Cited via 03.09.18-berger-holonomy.md; deferred to a future Joyce audit.
  • Algebraic-geometry-side cohomology of Kähler manifolds (Lefschetz hyperplane theorem, Bertini, Kodaira-Akizuki-Nakano vanishing, Kodaira embedding, projective embedding of Kähler varieties of restricted type). Sits in the 04-algebraic-geometry/ chapter and is partly shipped (04.09.02-kodaira-vanishing.md); not on this audit's scope.
  • Index theory for the Dolbeault operator (Riemann-Roch, Hirzebruch-Riemann-Roch, Atiyah-Singer for ). Touched in 03.09.10 (Atiyah-Singer) and 04-algebraic-geometry/04-riemann-roch/; not on this audit's scope.
  • Yang-Mills / instanton theory specifics (ASD equations, Donaldson invariants, ADHM construction). Fast Track 3.20 (Donaldson- Kronheimer / Atiyah-Bott) is the canonical audit target. Deferred.
  • The , , and Calabi-Yau holonomy specialisations. Joyce-territory; deferred.

§6 Acceptance criteria for FT equivalence (KN-II)

Per docs/plans/FASTTRACK_EQUIVALENCE_PLAN.md §3.4, the book is at equivalence-coverage when:

  • ≥95% of KN-II's named theorems in Chs. VIII–XII map to Codex units. Current ~25–30%; after priority-1 rises to ~65%; after priority-1+2 to ~85%; after priority-1+2+3 to ~93%; full ≥95% requires priority-4 weaving (no new units, only cross-references).
  • ≥90% of KN-II's worked computations in Chs. IX + XII (the load-bearing chapters) have either a direct unit or a worked example in a cross-referenced unit. Canonical KN-II computations to cover: as a Kähler manifold; the Hopf bundle as a holomorphic line bundle and its first Chern class; the Fubini-Study metric; the Pfaffian computation of ; the second Chern class of an -instanton over .
  • The source: TODO_REF for KN-II §XII in 03.06.06-chern-weil-homomorphism.md is resolved to a concrete chapter/section locator.
  • The TODO_REF blocks in 05.06.01-almost-complex.md and 05.06.03-newlander-nirenberg.md for the complex-geometry secondary references (Cannas da Silva, Huybrechts, Voisin) are resolved.
  • The Milnor-Stasheff-shared item (03.06.18 Chern-Weil / Milnor-Stasheff compatibility) ships once and is cited from both audits without duplication.
  • The KN-I-shared items (priority-0 above) ship once and are cited from both audits.
  • 03.09.18-berger-holonomy.md and 04.09.01-hodge-decomposition.md and 04.09.02-kodaira-vanishing.md and 05.06.01-almost-complex.md and 05.06.03-newlander-nirenberg.md carry weaving paragraphs pointing to the new complex / Kähler / Chern-Weil units.
  • Notation decisions are recorded in 03.02.09, 03.02.10, 03.02.11, 03.02.12, 03.05.19, 03.05.20, 03.06.07, 03.06.18 (especially the Kähler-form vs connection-1-form clash resolution; see §4).
  • Originator-prose citations of Chern 1946, Weil 1949, Newlander-Nirenberg 1957, Kodaira 1954, Chern-Simons 1974, Hodge 1941, Nomizu 1954, and Bochner 1946 are present in the relevant units.

The 6 priority-1 units close the complex / Kähler / Chern-connection silent-dependency gaps and lift KN-II coverage from ~25% to ~65%. Priority-2 (4 units) closes the Chern-Weil deepenings (transgression, Milnor-Stasheff compatibility) and the submanifold-equations gap. Priority-3 (3 units) closes the homogeneous-space / Bochner gaps. Priority-4 is weaving only and does not add new units.


§7 Sourcing

  • Not free. KN-II is under active Wiley copyright (1969, reprint 1996). Same legal status as KN-I — no free legal PDF is hosted by the authors' institutions or by Wiley. Print copies (Wiley Classics Library reprint, ISBN 0-471-15732-5) are readily available second-hand. Library mirror or Anna's Archive likely needed for a local copy; the Fast Track entry currently holds only the cover-image stub already shared with KN-I (reference/fast-track/images/Kobayashi-Nomizu-1-683x1024__72960fe9e3.jpg) — note that this stub may show only the Vol. I cover; the Vol. II cover image is not in the archive at the time of this audit.
  • Local copy. Not present in reference/textbooks-extra/ or reference/fasttrack-texts/03-modern-geometry/ at the time of this audit. A scanned copy should be added to reference/fasttrack-texts/03-modern-geometry/Kobayashi-Nomizu-FoundationsVol2.pdf before the production pass on the priority-1 punch-list units, so that line-number citations can be resolved in the TODO_REF blocks of 03.06.06 and in the new units that will cite KN-II Chs. IX + XII at master tier.
  • Companion peer texts (cited in §1):
    • R. O. Wells, Differential Analysis on Complex Manifolds, GTM 65, Springer 3rd ed. 2008 (with new appendix by O. García-Prada). The standard graduate text on the analytic side of complex geometry; Chs. I–III parallel KN-II §IX with a sheaf-theoretic rather than principal-bundle framing. The preferred secondary anchor for 03.02.10, 03.05.19, 03.05.20.
    • D. Huybrechts, Complex Geometry: An Introduction, Universitext, Springer 2005. The most accessible modern graduate text; Ch. 2 covers almost-complex / complex / Hermitian / Chern connection, Ch. 3 covers Kähler manifolds, Ch. 4 covers Hodge theory and Lefschetz decomposition, Ch. 5 covers Kähler-Einstein and Calabi-Yau. The preferred secondary anchor for 03.02.0903.02.12 and 03.05.1903.05.20.
    • C. Voisin, Hodge Theory and Complex Algebraic Geometry I + II, Cambridge Studies in Advanced Mathematics 76 + 77, CUP 2002–2003. The canonical modern treatment of Hodge theory on compact Kähler manifolds. Fast Track 3.27. Voisin §3 + §6–§8 directly parallels KN-II §IX.7 + Hodge decomposition; deeper Hodge-theoretic material is deferred to the FT 3.27 audit (see §5).
    • L. Tu, Differential Geometry: Connections, Curvature, and Characteristic Classes, GTM 275, Springer 2017. The most accessible modern rewriting of KN-I + KN-II §XII; Chs. 22–25 are a teaching rewrite of the Chern-Weil construction. The preferred secondary anchor for 03.06.06, 03.06.07, 03.06.18 (alongside KN-II).
    • J. Milnor, J. Stasheff, Characteristic Classes, Annals of Math. Studies 76, Princeton University Press 1974. Fast Track 3.08. The canonical topological / classifying-space construction of characteristic classes — the contrast to KN-II §XII. Appendix C of Milnor-Stasheff is the explicit bridge to Chern-Weil. Audit shipped this Cycle 4 (plans/fasttrack/milnor-stasheff-characteristic-classes.md); coordinate on the 03.06.18 compatibility unit.
    • S. Helgason, Differential Geometry, Lie Groups, and Symmetric Spaces, Graduate Studies in Mathematics 34, AMS 2001. The standard reference for homogeneous and symmetric spaces; Chs. IV–VIII parallel KN-II §X. Secondary anchor for 03.03.X2, 03.03.X3.
    • M. P. do Carmo, Riemannian Geometry, Birkhäuser 1992. Already cited in the KN-I plan; Ch. 6 covers submanifold geometry (Gauss-Codazzi-Ricci) at a gentler pace than KN-II §VIII. Secondary anchor for 03.02.13, 03.02.14.
    • H. B. Lawson, M.-L. Michelsohn, Spin Geometry, Princeton Mathematical Series 38, Princeton University Press 1989. Fast Track 3.10. §II.8 covers the Bochner technique in the spin / Dirac-operator setting. Secondary anchor for 03.02.15.
  • Originator-paper archive locations:
    • Chern 1946 Annals — JSTOR.
    • Weil 1949 lectures — collected in Œuvres scientifiques Vol. III (Springer 1979); print only.
    • Newlander-Nirenberg 1957 Annals — JSTOR.
    • Kodaira 1954 Annals — JSTOR.
    • Chern-Simons 1974 Annals — JSTOR.
    • Hodge 1941 Harmonic Integrals — Cambridge University Press; print only.
    • Nomizu 1954 Amer. J. Math. — JHU Press / JSTOR.
    • Bochner 1946 Bull. AMS — AMS journals.

§8 Coordination with sibling audits (Cycle 4)

The KN-II audit overlaps three sibling audits shipped or in flight this Cycle 4:

  1. KN-I (FT 3.18) — plans/fasttrack/kobayashi-nomizu-foundations-vol1.md. Strict prerequisite chain. The KN-II priority-0 units (torsion / Cartan structural equations, Levi-Civita / Hopf-Rinow, associated bundle / induced connection) are already on the KN-I priority-1 punch-list. Production order: KN-I priority-1 must precede KN-II priority-1. The KN-II Chern-connection unit (03.05.20) is the complex-bundle specialisation of the KN-I 03.05.13 (associated bundle and induced connection); cross-reference both.
  2. Milnor-Stasheff (FT 3.08) — plans/fasttrack/milnor-stasheff-characteristic-classes.md. The 03.06.18 (Chern-Weil ↔ topological compatibility) unit is shared. Milnor-Stasheff approaches characteristic classes from the homotopy / classifying-space side; KN-II approaches them from the curvature side. The compatibility unit is the bridge and should ship as a co-authored unit citing both anchors at master tier.
  3. Voisin (FT 3.27) — not yet audited. Voisin is the deep Hodge-theoretic sequel to KN-II §IX. The KN-II priority-1 unit 03.02.12 (Kähler identities + Hodge decomposition) is the upstream of Voisin's programme; Voisin's audit should treat 03.02.12 as a prerequisite anchor and pick up at Lefschetz decomposition / primitive cohomology / polarised Hodge structures.

The three audits together close the complex-and-characteristic-classes spine of the modern-geometry chapter (FT 3.08 + 3.18 + 3.19 + 3.27). The Chern-Weil / Chern-connection / Kähler-Hodge subchain is the load-bearing centre of that spine, and the priority-1 + priority-2 units of this KN-II audit are the most-cited new units across all four sibling-audit punch-lists.