computo ergo sum

2026-10-15 · chapter Yang–Mills and the mass gapAppendicessignposts to a proof, figures and status · Kiichi, Shiori and Rin

The whole book Contents and reading orders
  1. Part 0 Entrance — how to read this book
  2. 0-01 How to read this book
  3. 0-02 One picture
  4. 0-03 Reading the problem statement word by word
  5. 0-04 Four dimensions in mathematics and four dimensions in physics
  6. Part 1 Mathematical preparation
  7. 1-01 Vector spaces and linear maps
  8. 1-02 What a group is
  9. 1-03 Lie groups and Lie algebras
  10. 1-04 SU(2) and SU(3)
  11. 1-05 Manifolds and tangent spaces
  12. 1-06 Differential forms and the exterior derivative
  13. 1-07 Vector bundles and connections
  14. 1-08 Probability and measure
  15. 1-09 Probability in infinite dimensions
  16. 1-10 Hilbert spaces and self-adjoint operators
  17. 1-11 Fourier analysis and distributions
  18. 1-12 Detour: what happens only in four dimensions
  19. Part 2 Physical preparation
  20. 2-01 Lagrangians and the action
  21. 2-02 The idea of a field
  22. 2-03 Electromagnetism is a gauge theory
  23. 2-04 Special relativity and spacetime
  24. 2-05 The bones of quantum mechanics
  25. 2-06 The harmonic oscillator and creation and annihilation
  26. 2-07 The idea of the path integral
  27. 2-08 Statistical mechanics and phase transitions
  28. 2-09 Detour: the gap and the correlation length in the Ising model
  29. 2-10 The relaxation time and the dynamical exponent z
  30. Part 3 Yang–Mills theory (classical)
  31. 3-01 The gauge principle
  32. 3-02 Non-abelian gauge fields
  33. 3-03 The action and the equations
  34. 3-04 Gauge theory as geometry
  35. 3-05 Instantons and topology
  36. 3-06 Detour: Donaldson and exotic R⁴
  37. 3-07 Yang–Mills inside the Standard Model
  38. Part 4 Quantisation
  39. 4-01 Canonical quantisation and the Hamiltonian
  40. 4-02 The path integral and Euclideanisation
  41. 4-03 Perturbation theory and Feynman diagrams
  42. 4-04 Divergences and renormalisation
  43. 4-05 The algebra of divergences
  44. 4-06 Asymptotic freedom
  45. 4-07 Dimensional transmutation and Λ
  46. 4-08 Gauge fixing and Faddeev–Popov
  47. 4-09 The axioms of quantum field theory
  48. 4-10 The Osterwalder–Schrader axioms and reconstruction
  49. 4-11 The definition of the mass gap
  50. 4-12 Detour: the perturbation series diverges
  51. Part 5 Lattice gauge theory
  52. 5-01 Wilson's lattice
  53. 5-02 The strong-coupling expansion
  54. 5-03 Reflection positivity and the transfer matrix
  55. 5-04 The infinite-volume limit and the cluster expansion
  56. 5-05 Weak coupling and the continuum limit
  57. 5-06 How U(1) differs from the non-abelian case
  58. 5-07 The Monte Carlo method
  59. 5-08 Measuring glueballs and the string tension
  60. 5-09 What to hold fixed when taking the limit
  61. 5-10 Lattice gauge theory with finite groups
  62. 5-11 Detour: Bakry–Émery and one-link integration
  63. Part 6 Constructive field theory
  64. 6-01 What constructive field theory is
  65. 6-02 Solvability in two dimensions and the Yang–Mills measure
  66. 6-03 Constructing scalar fields
  67. 6-04 The cluster expansion
  68. 6-05 The sequence of renormalisation group steps
  69. 6-06 Ultraviolet stability of three-dimensional Yang–Mills
  70. 6-07 Four dimensions
  71. 6-08 Triviality of φ⁴ in four dimensions
  72. 6-09 Stochastic quantisation and regularity structures
  73. 6-10 Where four dimensions stops
  74. 6-11 Obstacles other than divergence
  75. 6-12 Detour: "if 1/0 is given a symbol"
  76. Part 7 From the side of physics
  77. 7-01 How physics sees it
  78. 7-02 Mechanisms of confinement
  79. 7-03 The string picture
  80. 7-04 Large N
  81. 7-05 String theory and extra dimensions
  82. 7-06 How extra dimensions become invisible
  83. 7-07 Where gauge fields come from
  84. 7-08 Holography
  85. 7-09 The mass gap becomes geometry
  86. 7-10 Back to four dimensions
  87. 7-11 Supersymmetry and Seiberg–Witten
  88. 7-12 The sentence that plays the role of an equivalence principle
  89. 7-13 Where the way physics digs parts from mathematics
  90. Part 8 A dictionary of two languages — the physical and the mathematical view
  91. 8-01 How to read the dictionary
  92. 8-02 Dictionary A
  93. 8-03 Dictionary B
  94. 8-04 Dictionary C
  95. 8-05 The physical counterparts of our assumptions
  96. The map
  97. Part 9 Where things stand, and open tasks
  98. 9-01 How far the world has come
  99. 9-02 Where the two ways of digging part
  100. 9-03 Candidates for new concepts
  101. 9-04 The list of open tasks
  102. 9-05 Common misconceptions
  103. 9-06 The stages a proof must contain — the table of seven stages
  104. 9-07 A map of the tools — where the known tools used by this book live
  105. The first road — from the direction of time
  106. Part 10 The first road, first half — from the direction of time: the mass gap and the diffusive-relaxation-time assumption
  107. 10-00 Entrance — the staircase, and the random walk, the ruler and the clock
  108. 10-01 The line of construction and Assumption ξ²
  109. 10-02 Roads tried on the four-dimensional lattice, and walls
  110. 10-03 The four steps of the staircase — why we start from 0+1 dimensions
  111. 10-04 The path measure of the double well, and kinks
  112. 10-05 The statement of the first step — four conditions and Proposition 4.5
  113. 10-06 (H1) Local Poincaré within a phase
  114. 10-07 The map of (H2) — seven routes and the seam of the ring
  115. 10-08 What computer-assisted means — the conditions on the chain inside the window
  116. 10-09 The sector framework and the three strands of route 5
  117. 10-10 The list of detour plans — types of breakage
  118. 10-11 (H3)(H4) and the constant of the core
  119. 10-12 The integrated table and the dependency graph
  120. 10-13 Lean statements and the limits of machine checking
  121. 10-14 Reconciliation — the numbers of the record and the known numbers
  122. 10-15 What remains and its cost — the distance to a theorem
  123. 10-16 What is not claimed
  124. 10-17 Insights and small questions
  125. Part 11 The first road, second half — repairing the form of the assumption, making time continuous
  126. 11-00 Further considerations — entrance
  127. 11-01 One form that obstructs Assumption ξ² — a nearly conserved global quantity
  128. 11-02 Choosing the ruler and the coordinates again — the length at which conservation breaks
  129. 11-03 Two ways to repair Assumption ξ² — the sector Assumption ξ² and the local Assumption ξ²
  130. 11-04 Which Assumption ξ² the one-sided bridge needs
  131. 11-05 Making time continuous — the Hamiltonian lattice and the vacuum measure
  132. 11-06 Paying with rarity instead of convexity — renormalisation on groups and log-Sobolev
  133. 11-07 Because it is four dimensions — the dimensionless coupling and topology
  134. 11-08 Questions, and what is not claimed
  135. 11-A1 Table of notation for Part 11
  136. The second road — from the direction of space
  137. Part 12 The second road: from the direction of space — a small twisted T² and confinement
  138. 12-00 Entrance — space, not time
  139. 12-01 The twisted T² and 't Hooft flux
  140. 12-02 Vortices and fractional instantons
  141. 12-03 Containers — conditioning on the frame makes things independent
  142. 12-04 Slab confinement
  143. 12-05 Vortex-insertion identities
  144. 12-06 Driven insertion and the flow lemma
  145. 12-07 Why fixed maps fail
  146. 12-08 The measured record
  147. 12-09 Where this road stops — widening the T² is the band
  148. The crossover band — two roads reach the same wall
  149. Part 13 The crossover band — two roads reach the same wall
  150. 13-00 Entrance — confluence
  151. 13-01 The correct form of the band
  152. 13-02 Reduction to a single inequality
  153. 13-03 The only place where non-abelian enters
  154. 13-04 Structure alone cannot cross
  155. 13-05 The chessboard and simultaneous flips
  156. 13-06 Renormalisation comparison — a comparison that distinguishes groups
  157. 13-07 The band seen from the side of time
  158. 13-08 A map of the roads tried and stopped
  159. 13-09 The measured record
  160. 13-10 Candidate new viewpoints
  161. 13-11 Ultraviolet control — what it means to close at infinitely many steps
  162. Closing
  163. Part 14 Closing — conditional statements
  164. 14-00 Entrance — the promise of this part
  165. 14-01 The conditional statement — the mass gap and confinement, arrow by arrow
  166. 14-02 The ledger of conditions
  167. 14-03 The table of questions (a cross-index)
  168. 14-04 What is not claimed (a cross-index)
  169. The ultraviolet wall — the foundation beneath both roads
  170. Part 15 Ultraviolet control — what it means to close at infinitely many steps
  171. 15-00 Entrance — what ultraviolet control is
  172. 15-01 Why the ultraviolet is hard — dimensionless coupling, group-valued fields, gauge
  173. 15-02 A map of the sources — Bałaban's programme, the BBS chain, two rows absent from the sources
  174. 15-03 The decomposition statement — a class that closes with finitely many parameters, and three remainders
  175. 15-04 The one-link heat-kernel class and the hierarchical model
  176. 15-05 The flux-network theorem — the transverse contraction and the parameter flow in one projection
  177. 15-06 Counting the parameters — couplings by loop shape and the attracting class
  178. 15-07 Background-dependent fluctuations η — absorption step by step
  179. 15-08 The four rows that do not close, and proposals for them
  180. 15-09 What cannot be said, the index of questions, the dependency diagram
  181. Appendices
  182. A-01 Table of notation
  183. A-02 Glossary
  184. A-03 Guide to the literature
  185. A-04 Lean and machine checking
  186. A-05 How this book was made
  187. A-06 Index of assumptions
  188. A-07 Papers that came out of this book
  189. A-08 私達の研究における証明までの道標

Signposts to a proof in our research

This chapter is a guide (signposts to a proof). It lays the rows of the ledger of conditions on a chain diagram in two layers, our predecessors and this book, and marks what has closed and what remains open.

What this chapter gives — How far the work of this book is closed towards a proof of existence and mass gap for Yang–Mills, what is conditional, and what is open. The ten rows of the ledger of conditions (14-02ledger) and the four gaps outside it are drawn as one chain; each box is split into what earlier work closed and what this book added. The two core rows (① ultraviolet control, ⑦ renormalisation comparison) get their own figures.

Prerequisites — 14-01conditional statement, 14-02ledger. For the labels see 10-00entrance; for notation a-01notation.

Said first — The figures are signposts, not a progress gauge. The colours are the state on 2026-10-15; the rule for when a row disappears is that of 14-02ledger §01. This book does not claim a solution of the Yang–Mills existence and mass gap problem (14-04non-claims).


00

Role of this chapter

  1. The road to a proof is drawn on one page as a chain of the ledger rows (①–⑩) and the gaps outside the ledger (Out 1–4).
  2. Each box separates what earlier work closed (source and year) from what this book added (with labels).
  3. What is shown is "closed", what is shown under conditions is "conditional", what is not shown is "open".
  4. The two core rows, ① and ⑦, are broken down in separate figures.
  5. How to read: take the whole picture in Figure 1, go from the red boxes to Figures 2 and 3 and Table 1, and jump to the text from the chapter tags (for example 14-02).
01

Legend and labels

closed — closed on paper or in Lean (within the conditions written in the row).
conditional — closed under conditions; the conditions remain as numbers (measured ranges, finite β) or readings (numerics, sketches).
open — not shown.
earlier work — the grey strip on top of a box: source and year of what earlier work closed (bibliography in a-03bibliography, 15-02sources, 9-07tools).

Difficulty is not counted in stars but read from the five labels of this book: Proved here = a paper proof placed in a chapter of this book / Cited = known, checked in the source / Computer-assisted = computer-assisted (interval arithmetic) / Reading = numerical reading / Assumption = assumption or sketch. For an open box, read the difficulty from the labels and from "what is needed to remove it" (14-02ledger Table 2). Thick frames mark the core (① and ⑦).

02

Figure 1: the whole chain — earlier work and this book

The boxes of Figure 1 are the ledger rows (①–⑩) and the gaps outside the ledger (Out 1–4). Arrows point from premise to conclusion, and every row has a larger number than its premises (the layer order of 14-02ledger §04). The grey strip on top of a box is what earlier work reached; the colour at the bottom is what this book reached. A strip reading "—" marks a condition stated in this book's own terms, with no statement of the same form in the sources. Clicking a box opens the chapter that treats the row.

Bałaban 1983–89 (partly unpubl.) ① UV control decomposition, Lemmas F, LS, LF open 15-03 Osterwalder–Seiler 1978 ⑤ reflection positivity twist-summed, Lean closed 13-04 't Hooft 1979 (twist) ② gap on small T² twist part; uniformity needs ① conditional 12-01 — ③ insertion acceptance identities; acceptance assumed conditional 12-06 — ⑥ frame decorrelation fixed L: one density κcb conditional 13-05 Tanizaki–Ünsal (one loop) ④ base point on T² lattice version assumed conditional 12-02 Wilson 1974, Gross–Wilczek 1973 ⑦ RG comparison both ends; band interior open open 13-06 — ⑩ 4D target (time) one-sided bridge under ξ²↑ conditional 10-15 — ⑧ the band reduction from ④⑥⑦, Lean conditional 13-02 Bakry–Émery (convex side) ⑨ first-step remainder convex side closed in record conditional 10-09 Osterwalder–Schrader 1973 Out 1 limit to R⁴ only a sketch open 14-02 — Out 4 verification ← all rows open 9-04 — Out 2 area law → gap statement not yet fixed open 9-06 — Out 3 all groups SU(N) expected open 9-04

Figure 1. The chain to a proof (2026-10-15). Thick frames: the core rows ① and ⑦. The dotted line between ⑨ and ⑩ means "miniature", not implication. Out 4 (verification) has every row as premise, so its arrows are omitted. On a narrow screen, scroll sideways.

What to read from Figure 1. (a) The strip of earlier work is thick at ⑤ (reflection positivity), at both ends of ⑦ (strong coupling and one loop) and at ① (Bałaban's series); this book adds parts that fit the group, the twist and the form of the measure there. (b) Among the parts added by this book, only ⑤ is closed; the rest is conditional or open. (c) The red boxes are ①, ⑦ and the gaps outside the ledger; the interior of the band in ⑦ (where non-commutativity acts) and the multi-step induction of ① are the wall shared by both roads.

03

Figure 2: inside ① ultraviolet — four cells

Ultraviolet control ① is split by the decomposition of Part 15 (15-03decomposition) into "a class closed under finitely many parameters" and three remainders. Figure 2 colours the four cells by today's state. Earlier work: Bałaban's series (1983–1989, including steps the source describes as unpublished; 15-02sources), centred on small-field steps around flat fields.

Cell 1 class (Cls)

A one-parameter class towards which the one-step map pulls. In four dimensions, the proposal "one parameter plus ratio coordinates fixed by the flow" Assumption. Existence of the fixed point and rule-dependent values remain; the difficulty concentrates here.

15-03decomposition15-07background

Cell 2 one-step remainder (S)

(S)+(C) ⇒ (U3) is Lemma F Proved here. The large-field part: Lemmas LS, LF Proved here. The local small-field part has the same form as the flat-field source CitedProved here (conditional). Open: the group version of the local cancellation in four dimensions, and the multi-step recursion.

15-08four rows15-03decomposition

Cell 3 shape remainder (Rem-shape)

With the background as a class parameter, Σηk is finite under conditions ReadingProved here (two links, a row of four plaquettes). For one and two plaquettes the absorption is exact Proved here. The blocking condition for many steps remains.

15-07background15-06parameters

Cell 4 continuity (C)

Continuity inside the domain; with (S) it gives (U3) through Lemma F Proved here. At the seams of gauge re-fixing: existence and uniqueness of the tree gauge Proved here (finite groups in Lean). Backgrounds away from critical points remain.

15-03decomposition15-08four rows

Figure 2. The four cells of ① (2026-10-15); the coloured edge is the state. The flux-network theorems F, G and the row-of-four theorem U are in 15-05flux network and serve as parts of cells 2 and 3.

04

Figure 3: the β map of ⑦

The renormalisation comparison ⑦ splits into five regions along the Wilson coupling β (13-06renormalisation). The two ends rest on earlier tools (strong-coupling expansion: Wilson 1974, Osterwalder–Seiler 1978; one loop: Gross–Wilczek, Politzer 1973), with the group and the twist fitted in by this book; the middle is closed by nobody's tools.

strong coupling β≲10⁻⁷⁹ closed ⑦a lower end push to β≈0.3–1 open ⑦c middle non-abelian inequality open ⑦b upper end semiclassics, fixed N conditional one loop β−β′=0.258 closed β 0 SU(2): β′<β at every β U(1): sign flips at β_c≈1.01 direction of the one-step coupling shift (shape only, no scale)

Figure 3. The β map of ⑦ and the direction of the one-step coupling shift (shape only, no scale; the numbers with lattice, seeds and errors are in 13-09record). SU(2) has β′<β across the band, U(1) flips sign at βc≈1.01 Reading. The one-loop comparison β−β′=0.258 is Proved here at one-loop level (not a non-perturbative claim).

An argument closing the band must distinguish SU(2) from U(1): U(1) has a transition inside the band, where an inequality of the form ⑦ fails. The middle region ⑦c needs "one inequality that uses non-commutativity", with four faces (softness of the twist direction, mixing of box fluxes, cost of twisting a column, pressure margin); none is proved Assumption. A fifth candidate face (proposal SD) gives R=1.34(7) (4⁴/2⁴) and R=1.17(20) (6⁴/3⁴) in finite boxes, within resolution, so undecided Reading (15-04hierarchical).

05

The other road — the wall of Part 10 (from the time direction)

The first road goes to the mass gap through the transfer matrix in the time direction. The chain of statements (10-15remaining distance, 10-12integrated table):

  1. Construction line (10-01construction) — Langevin path measures on the lattice, and the one-sided bridge: the inverse squared gap bounds the Poincaré constant from below Proved here (published as a paper, a-07papers).
  2. First step (10-05first step) — for the double-well path measure, the convex side (chain length ≤7) and uniqueness of the minimum are closed in the record; the section placing them in the book is a supplement Assumption.
  3. ⑨ first-step remainder — a gap uniform in k and ℏ for chain length k≥8 (a uniform log-Sobolev inequality including non-convex regions) Assumption. A miniature of the band.
  4. ⑩ four-dimensional target — the upper side ξ²↑ of the diffusive relaxation-time assumption (formerly hypothesis H↑) and the one-sided bridge, uniform as β→∞ Assumption.

Today ⑨ and ⑩ stand in conditional form; removing ⑨ does not move ⑩ (⑨ is a miniature, not an implication). ⑩ means crossing the band in the language of time, and it stops at the same place as ⑦ on the second road (13-07from time).

05b

Three classes by chapter — summary by part

The same state is drawn in three views: the chain map (Figures 1–3), the classification by chapter (this section), and the dependencies of Part 10 (§05 and 10-12integrated table). This section sorts the chapters of the book into three classes and counts them by part.

Table 0a. Legend of the three classes
ClassContentLabels of this book
(a) reduced to known theoremstheorems of the literature, restatements, external checksCited
(b) claims of this book, checkedpaper proof placed in the text, checked in Lean, computer-assisted (within the measured range only)Proved here, Lean, Computer-assisted
(c) unproved, assumedassumption rows, numerical readings, claims at the physics levelAssumption, Reading
Table 0b. Summary by part (2026-10-15, 165 chapters; the class is the main content of a part, not every row)
PartChaptersMain classPointsChapters
Parts 0–445(a)basic mathematics and physics; very few proofs of this book0-01how to read4-11mass gap
Part 511(a) + numericslattice and strong coupling; claims of this book gather in the one-link detour5-03reflection positivity5-11one link
Part 612(a) + (c)constructive field theory; the four-dimensional wall organised from the literature6-07four dimensions6-10where it stops
Part 713(c)views at the physics level; not placed as mathematical claims7-02confinement7-13where physics leaves
Parts 8, 912(a) / (c)dictionary, timeline, open tasks, seven stages, map of tools9-04open tasks9-06seven stages9-07tools
Part 1018(b) + (c)111 rows of the first step = Proved here 48, Cited 10, Computer-assisted 4, Reading 19, Assumption 30; the ratio is not progress10-12integrated table10-15remaining distance
Part 119(b) + (c)the one-sided bridge closed on paper and published; ξ²↑ and the sector and local assumptions open11-04bridge11-08questions
Part 1210(b) + (c)twist part and insertion identities proved here; acceptance and base point assumed12-01twisted T²12-05insertion12-09where it stops
Part 1312(b) + (c)⑤ reflection positivity, reduction to ⑧ (Lean), one-loop level; inside the band in ⑦ open13-02reduction13-06renormalisation13-09record
Part 145summaryconditional statement, ledger, questions, non-claims14-01statement14-02ledger14-04non-claims
Part 1510(b) + (c)Lemmas F, H, LS, LF, Theorems U, F, G, tree gauge proved here; 4D cancellation and many steps open15-03decomposition15-05flux network15-08four rows
Appendices8summarynotation, glossary, bibliography, Lean bundles, how checked, index of assumptions, papers, this chaptera-04Leana-06assumptionsa-07papers

A table classifying every chapter (grouped by ranges of chapters) and the vertical dependency diagram of Part 10 (conditions (H1)–(H4) and the two routes) will be added in the next version of this chapter. For now the dependencies of Part 10 are read in Figure 1 of 10-12integrated table and in 10-15remaining distance.

06

Table of tasks

Table 1. Tasks on the way to a proof (2026-10-15; colours as in Figure 1; each state within the conditions of its row)
RowConditionStateLabelsEarlier workThis bookChapters
①ultraviolet controlopenProved here, Cited, Reading, AssumptionBałaban 1983–1989 (around flat fields; some steps unpublished)four-cell decomposition, Lemmas F, LS, LF; (S_small) of the source form under conditions; 4D cancellation and multi-step open15-03decomposition15-08four rows15-09UV index
②gap on small T²conditionalProved here, Assumption't Hooft 1979 (twisted boundary conditions)twist part (unique vacuum, Laplacian gap); uniform form under ①12-01twisted T²
③uniform acceptance of insertionsconditionalProved here, Reading, Assumption—insertion identities; uniform acceptance assumed under ①; longer protocols lower the work in measurements12-05insertion12-06driven12-08record
④base point on small T²conditionalCited, AssumptionTanizaki–Ünsal (arXiv:2201.06166, dilute regime, one loop)deriving it on the lattice from ①, ③ is assumed12-02fractional instantons
⑤reflection positivity in zclosedProved here, LeanOsterwalder–Seiler 1978 (lattice gauge reflection positivity)positivity for the twist-summed ensemble, chessboard estimate (Lean: ReflPos)13-04structure13-05chessboard
⑥frame decorrelationconditionalProved here, Assumption—for fixed L, one density κcb via chessboard from ⑤; uniform in L assumed13-05chessboard
⑦renormalisation comparisonopenProved here, Reading, Assumptionstrong coupling: Wilson 1974, Osterwalder–Seiler 1978 / one loop: Gross–Wilczek, Politzer 1973 / hierarchical: Migdal–Kadanoff (15-02sources)both ends booked with group and twist; one-loop comparison; the step distinguishing groups inside the band is open13-06renormalisation13-09record15-04hierarchical
⑧the bandconditionalProved here, Lean, Assumption—reduction from ④, ⑥, ⑦ (Lean: Doubling); the band itself assumed13-01band13-02reduction
⑨first-step remainderconditionalAssumptionBakry–Émery (convex side, 9-07tools)convex side (length ≤7) and unique minimum closed in the record; uniformity for k≥8 open10-09three strands10-15remaining distance
⑩4D target (time side)conditionalProved here, Assumption—one-sided bridge under ξ²↑; the assumption itself open10-01construction10-15remaining distance13-07from time
Out 1limit to R⁴openAssumptionOsterwalder–Schrader 1973, 1975 (axioms and reconstruction)only a sketch that most is standard under ⑧14-02ledger9-04open tasks
Out 2area law to gapopen——the statement of what to add is not fixed9-06seven stages14-02ledger
Out 3all compact simple groupsopenCited, Readingwithout centre the vortex tools fail (9-04open tasks)SU(N) expected to carry the flux over (physics reading)9-04open tasks14-02ledger
Out 4verificationopen——full write-up, Lean where reachable, refereeing, publicationa-04Leana-05how checked
07

Closed, conditional, open

Closed (on paper or in Lean)

  • ⑤ reflection positivity (Lean: ReflPos) 13-04structure
  • row-of-four theorem U, flux-network theorems F, G 15-05flux network
  • existence and uniqueness of the tree gauge 15-08four rows
  • Lemmas H, LF, LS, F 15-07background15-03decomposition
  • Proposition O (orbit-direction Hessian = 0) 15-01why UV is hard
  • algebra of the reduction to ⑧ (Lean: Doubling) 13-02reduction
  • the one-sided bridge a-07papers

Conditional

  • the wall of Part 10, ⑨ and ⑩ 10-15remaining distance
  • computer-assisted chain of the hierarchical model (β≤128) 15-04hierarchical
  • the 4D tree cone (first step) 15-08four rows
  • Σηk with the background as a parameter 15-07background
  • (S_small) in the form of the source 15-08four rows
  • ②, ③, ④, ⑥, ⑧ 12-01twisted T²12-06driven13-02reduction

Open

  • ① 4D cancellation in (S_small) and many steps 15-08four rows
  • ① fixed point of the class (Cls) 15-03decomposition
  • ⑦ the step distinguishing groups inside the band (four faces of ⑦c) 13-06renormalisation
  • Out 1 limit to R⁴, Out 2 area law to gap 14-02ledger
  • Out 3 all groups, Out 4 verification 9-04open tasks
08

Order of next steps

Five steps chosen from the table of questions (14-03questions) and the questions of Part 15 (15-09UV index), premises first. Each is a small question; settling it does not by itself close ① or ⑦.

  1. ① cell 2: on a slab (many links), measure the difference in total variation between densities with and without one large-field region, and see whether (S_large)≤C′g² holds in the smallest system (F-UV12). 15-08four rows
  2. ① cell 3: check whether the parity at the critical point holds for four plaquettes; if so, the background uniformity of (S_small) weakens (F-UV14). 15-08four rows15-07background
  3. ① sources of observables: add a source to one loop in a row of four plaquettes and measure whether the coupling shift after one step is independent of β (F-UV13). 15-08four rows
  4. ⑦a lower end: turn the finite-size criterion by mixing of box fluxes into a certificate with interval arithmetic. 13-06renormalisation15-04hierarchical
  5. ⑦c middle: write one of the four faces uniformly in scale, in a form that fails for U(1); decide proposal SD in boxes of higher resolution. 13-06renormalisation13-10candidates
09

What cannot be said, notes

The lists of non-claims are in 14-04non-claims and 15-09UV index. Three are specific to this chapter. (1) Counting the colours in Figure 1 does not give a fraction of the way (the ledger is not a table that only shrinks, 14-02ledger §06). (2) The strips of earlier work summarise what the sources reached; they are not the statements of their theorems. (3) Even if every box turned green, that would not amount to a solution of the problem (Out 1–4 are gaps outside the ledger, shown in Figure 1 to make the distance visible).

Notes — Notation: ① ultraviolet control, (Cls) class, (S) one-step remainder, (Rem-shape) shape remainder, (C) continuity, (U3) the effective coupling stays small (15-03decomposition). ⑦a, ⑦b, ⑦c are the lower end, upper end and middle of ⑦ (13-06renormalisation). ξ²↑ is the upper side of the diffusive relaxation-time assumption (formerly hypothesis H↑, a-06assumptions). βc≈1.01 is the U(1) transition inside the band.

What this chapter can say

Can sayCannot say
The state and labels on 2026-10-15 of the ten ledger rows and the four outside gaps (copied from the chapters)A proof of any row; this chapter adds no new results
For each row, the border between what the sources closed and what this book addedAll that the sources reached (this is a summary)
Five next stepsThat settling them closes ① or ⑦

Sources and reproduction

ItemKindSource
rows, states, labelsthis book14-02ledger, 14-01conditional statement, 15-09UV index, 13-06renormalisation
what earlier work reachedCiteda-03bibliography, 15-02sources, 9-07tools; years as in the bibliography
directions in Figure 3Reading13-09record (lattices, seeds, errors)
problem statementCitedA. Jaffe, E. Witten, Quantum Yang–Mills Theory, Clay Mathematics Institute (2000)

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