Working notes · Network epistemology of proof
Extending Viteri & DeDeo (Cognition 2022) to the mathematics humans and machines are now writing together: new dependency-network data from four Lean megaprojects, three generations of AI provers, and the first quantitative pass at the correspondence problem.
The 2022 paper made three claims about how belief in a proof forms: proof networks have the topology (heavy-tailed re-use, α ≈ 2, high modularity) needed for an epistemic phase transition — a jump to near-certainty at realistic per-step error rates; modules act as firewalls that contain doubt; and deduction and abduction must stay balanced, or certainty collapses (the abductive paradox). Two later papers set the AI-era agenda: AlephZero and mathematical experience (DeDeo 2024) predicts automation transforms impasse, error, and aboutness; A correspondence problem for mathematical proof (DeDeo & Duede 2026) argues a formalization justifies a particular proof only if it represents its theorem and tracks its steps — and that AI-era pipelines weaken exactly the causal and explanatory provenance that tracking requires.
Between 2022 and 2026 the object of study changed under the instrument: mathlib passed two million lines; Tao's PFR formalization took three weeks; the Equational Theories Project (ETP) settled all 22,028,942 implications among 4,694 magma laws with humans, ATPs, and LLMs in one repository; AlphaProof reached IMO silver; Gauss finished the sphere-packing formalization in five days and autoformalized the dimension-24 case from the original paper in two. Every one of these projects publishes its full dependency structure. The 2022 methodology can simply be pointed at them.
For each of four flagship projects — PFR (teorth/pfr), FLT (ImperialCollegeLondon/FLT), Sphere Packing (human-led repo and Math Inc's AI-completed fork), and Equational Theories (teorth/equational_theories) — two networks were extracted:
\uses{} declarations. These are the direct descendants of the
hand-coded Euclid/Wiles/Herstein networks of 2022 — with the difference that the community now
writes the network itself as a working document.theorem/lemma/def …); edges are textual references from one
declaration's statement or proof to another. AlphaProof's raw IMO 2024 outputs, human formalizations of the
same three problems (J. Myers, mathlib Archive), and AlphaProof Nexus's 2026 research-level corpus
(2,494 theorems) were analyzed at the finer intra-proof grain: named-claim networks inside each proof.Method caveat. Lean graphs here are textual (no compilation), so edges mediated by
simp-sets or mathlib intermediaries are missed and suffix-matching admits some noise;
absolute edge counts are lower bounds and cross-corpus comparisons are the meaningful quantity.
Statistics are computed on largest weakly-connected components; α by discrete Clauset–Shalizi–Newman MLE;
belief dynamics by the paper's asymmetric-Ising Glauber model (pprior = 0.75, 10 sweeps);
ΔL₁ firewall statistic per the 2022 appendix at β = 1.
Kernel-grain validation (all four compiled projects). Each project was
compiled and its ground-truth dependency graph extracted from the kernel environment
(Expr.getUsedConstants over every constant's type and proof term). Textual edges are
77–92% precise against kernel truth (PFR 92%, Sphere 92%, Gauss-sphere 88%, FLT 77%) with 52–59%
recall — the missing half is instance resolution, notation, and tactic-mediated uses, 68–87% of it
edges into definitions rather than theorems. α and Q agree between grains within errors on
every project. Tracking fidelity rises at kernel grain (PFR 73%→86%, FLT 47%→79%,
Sphere 54%→66%), confirming textual levels as lower bounds — with one telling exception:
Equational Theories barely moves (42%→43%), meaning its correspondence gap is real, not an
extraction artifact. The ET kernel corpus is the largest: 48,505 declarations, 336,491 internal
edges, α = 2.88 ± 0.07, with Magma reused 34,032 times. PFR alone makes 88,790
references into mathlib/core (≈68 per declaration); FLT 263,742; ET 272,961.
Data-quality audit (correction). A manual audit of the extracted graphs found
four defects in the original textual extractor: ASCII-only identifier regexes truncated Unicode Lean
names (z₁…z₆′ collapsed into one fake hub z; Greek-initial
declarations dropped entirely), the Lean 4.33 public modifier was unrecognized (hiding
55% of the Math Inc corpus), string literals could produce phantom declarations, and short global
names (G, f) matched same-named local variables project-wide. All were
fixed and every number in this report recomputed; the qualitative findings survived unchanged, but
several exponents moved (e.g. Math Inc α 1.94→2.51, ET human 2.08→2.52) and the cross-strata edge
counts halved. The kernel-grain graphs, extracted from compiled binaries, were never affected —
their agreement with the corrected textual numbers is itself evidence the pipeline is now sound.
Audit, second round. Further manual checks, each reading extracted data
against raw source. (1) Custom commands are a textual blind spot: ET defines its 4,694
equations via a bespoke equation N := … macro, so the textual grain sees 95
declarations in Equations/ where the kernel sees 14,278 — another reason the kernel
grain is authoritative for ET. (2) The certificate-dust claim survives ground truth, in stronger
form: at kernel grain the machine stratum's apparent internal edges are almost all
Law_X_implies_Law_Y → Equation_X_implies_Equation_Y — the same certificate auto-restated
at law level (exactly one such edge per certificate pair in SimpleRewrites, Vampire, brute-force,
and 4×4-table methods). Zero genuine certificate-to-certificate reuse; only the Greedy method's
human-designed PartialSolution machinery shows real internal structure. And the one-way
flow sharpens: 200,614 kernel edges human→machine, 37 back. (3) Compiler boilerplate is
negligible: auto-generated declarations (casesOn, rec,
noConfusion…) are 1.6–5.3% of kernel nodes; removing them shifts PFR kernel α from
2.46 ± 0.23 to 2.58 ± 0.27 — well within errors. (4) Blueprint extraction verified by hand:
in PFR's entropy chapter, 42 hand-counted \uses dependency mentions = 42 extracted
edges, multi-name \lean{} tags parse correctly, zero dangling references.
(5) The AI style trajectory re-counted from raw files: AlphaProof's 2024 P2 solution contains
a single have in the entire file; a sampled 2026 Nexus file has 255, of which 95% are
named — consistent with the corpus-wide 97% figure.
Audit, third round — adversarial robustness of the headline claims
(full numbers in results/robustness_summary.json).
(1) "α ≈ 2 power law" should be read as "heavy tail": a Vuong likelihood-ratio test cannot
distinguish power law from lognormal on four of the five kernel corpora (|R| < 1.96); only ET,
with a 665-declaration tail, statistically favors the power law (R = +3.6). At a fixed
xmin = 8 all five corpora sit at α = 2.1–2.6, and module-jackknife shows PFR's tail is
partly carried by its entropy toolbox. Heavy-tailed reuse with hubs is robust; the precise exponent
is not the load-bearing quantity. (2) The Wiles signature survives a grain control:
contracting Lean graphs to file level (matching blueprint size) leaves α at 2.1–3.0, still below
the blueprints' 3.3–4.6 — the hub deficit is a property of communication, not coarseness.
(3) Tracking is not a density artifact: random pairs of the same blueprint-tagged nodes
connect within 6 hops only 2–11% of the time, versus 44–86% measured — and ET's base rate equals
FLT's, so its correspondence gap is real. (4) The null-model decomposition replicates on FLT
(degree-keeping controls reproduce the real curve and firewall +12.5 to +13.7; modularity-destroyed
controls collapse to +4.4/+5.2), and a later grid extension corrected the ER reading: the ER
transition is sharp but sits at ε ≈ 0.44, outside the original grid — see "Is it actually a phase
transition?" above. Seed variation moves crossover estimates by < 0.01. A CSN goodness-of-fit
bootstrap adds: the power-law form is not rejected for PFR/FLT/Sphere/Gauss tails
(p = 0.15–0.85) and is rejected for ET (p < 0.01, ntail = 665) — heavy-tailed and
approximately power-law, with the strict form failing exactly where the data has power to test
it. (5) The asymmetry result is not an anchoring artifact: adding a persistent prior
field softens the pure-forward collapse (0.50 → 0.84) but the shape survives — mixed coupling still
wins, forward weight still favors the final theorem. (6) The sorry-clamping contrast holds
across seeds (FLT downstream −0.25 ± 0.09; Sphere −0.07 ± 0.10) though Sphere's earlier −0.007
was seed luck. (7) All 37 machine→human edges were read: they are genuine (the Sheffer
development and the Tarski543 proof, which chains nine machine certificates) — so "nothing flows
back" should read "0.15% of certificates have ever been reused by humans."
The parallel-task confound (audit, fourth round). An objection worth
taking seriously: the magma-implication problem was chosen for parallelizability — maybe
certificate dust reflects the task, not search. Two controlled tests
(results/et_depth_split.json). First, human-authored implications of the same
ordinary type are exactly as flat as machine ones (median construction-specific support 1 for
both; even at kernel grain, 46% vs 54% cite any intermediate at all) — so the dust of the easy
mass is indeed the task's doing, and the raw human-vs-machine strata comparison overstated the
generator's role. Second, holding the task fixed, depth splits by method: the 34 human
counterexample results carry median 33 (max 53) supporting constructions; the 1,078 machine Facts
carry uniformly ≤ 2 (a stamped template); the Greedy method — a human-designed framework
machine-instantiated per equation — sits between (tail to 31). The refined claim: search operated
precisely on the stratum of instances where no intermediate structure is needed, and every deep
instance that got solved was solved by construction. The α ≈ 2 economy is not something search
lacks; it is something deep problems demand, from whoever solves them.
The missing experiment, run (audit, fifth round). The confound above
demanded a corpus of search-generated proofs on mathematics not selected for
parallelizability. It exists: the Mizar40 experiments (Kaliszyk & Urban) had Vampire/E re-prove
32,524 theorems of the general Mizar Mathematical Library, recording the premises each minimized
ATP proof used, and the MPTP2078 benchmark encodes the human Mizar proof dependencies for
2,078 theorems on the track to Bolzano–Weierstrass. The intersection gives 1,274 theorems of
ordinary mathematics — topology, analysis, set theory — each with both a human and a
search-found proof (analysis/mizar_atp_compare.py,
results/mizar_atp_compare.json). Results, after removing MPTP background axioms:
ATP proofs are 3× leaner (5.1 vs 16.5 premises) and heavily rerouted — only 29% of the
premises an ATP uses appear in the human proof's dependency set. And the reuse economy differs in
the predicted direction: human premise reuse is hub-concentrated (α = 2.36 ± 0.09 on a
248-premise tail, Gini 0.740) while ATP reuse is flatter and hub-deficient (α = 3.18 ± 0.38 on a
33-premise tail, Gini 0.567); a size-matched control (human dependency lists subsampled to ATP
proof sizes, 20 reps) leaves human Gini at 0.669 ± 0.002, still well above the ATP — the gap is
not a proof-length artifact. Two caveats cut in opposite directions: Mizar40's premise selection
was kNN-trained on human proofs, biasing the ATP toward human routes (unbiased search would
diverge further), while ATP proof minimization may prune some genuinely-used context. The refined
conclusion of the previous note survives its cleanest test so far: on the same general-library
theorems, search finds valid but structurally different proofs — shorter, scattered, avoiding the
canonical toolbox that human proofs concentrate on.
Below the naming grain (sixth round): the 2019 term-sharing analysis, rebuilt
in Lean. The 2022 paper's Coq networks were hash-consed proof-term DAGs — reuse measured at
subterm grain, below named declarations (code: ManipulateProofTrees). We rebuilt that
algorithm over compiled Lean kernel terms (de Bruijn indices give exact α-equivalence; child
order and multiplicity preserved) and ran it on all 47,940 ET proof terms
(analysis/subterm_stats.lean, results/et_subterm_summary.json). The
naive expectation — dust all the way down — is wrong. Machine certificates have real internal
sharing: at matched term size (100–3,000 distinct subterms), machine and human proofs compress
identically (100.87 vs 100.88 tree-to-DAG), and the machine's most-repeated
subterm is referenced more (median max-refcount 39 vs 24). The difference is in character
and in fate. Human deep constructions achieve extreme, diverse compression — the Facts
counterexample towers median 102.0, and full_spectrum_Equation1682 packs
an expanded tree of ~1010.8 nodes into a 124,638-node DAG (one subterm used 3,101
times). Machine sharing is concentrated hammering: a heavier subterm-refcount tail (α 3.2 vs 4.1
size-matched) — the same expressions recurring down a rewrite chain. And crucially, the machine's
shared subterms stay inline: they are never factored into named declarations, so their
reuse dies at the term boundary. This localizes the dust result precisely: machine proofs are not
structureless — they are unfactored. What search lacks is not repetition but the act of
naming repeated structure into citable units, and that act is exactly what the α ≈ 2 economy,
the belief dynamics, and the refutation firewalls all run on.
Below is the actual network the statistics in this report are computed on — the largest connected component of PFR at kernel grain: 1,106 compiled declarations (nodes, sized by how often they are reused) and 5,344 kernel-verified dependency edges. Press play to run the 2022 paper's belief model live on it: each declaration is a spin that flips toward agreement with its dependencies and dependents, with per-step error rate ε. Drag ε and watch the epistemic phase transition — above the critical point belief stays patchy and mottled; below it, conviction crystallizes across the whole proof at once.
PFR_conjecture'. Dynamics: the paper's
Glauber model, couplings β = ½·ln((1−ε)/ε). Three things to try. (1) At the starting
ε ≈ 0.44 the network is near its critical point: the sparse periphery flickers indefinitely while
the hub core holds — persistent mottle. (2) Drag ε below ≈ 0.3 and the mottle crystallizes
to solid belief in a couple of sweeps; this one-way collapse into consensus is the epistemic
phase transition, and it is why low-ε views look uniformly blue. (3) Press "Doubt all" at
low ε: the network locks into solid disbelief and stays there — below the transition both
consensus states are stable (bistability), and which one you get depends on history, not evidence.
Raise ε near 0.5 to melt any locked state back to noise. "Color by part" pauses the dynamics and
shows the division of labor instead: the entropy toolbox, mathlib-bound patches, and the main
argument.| Network | N (LWCC) | α (out-degree) | Modularity Q | ΔL₁ firewall | f₂ @ ε=0.01 |
|---|---|---|---|---|---|
| Euclid, original text (2022 baseline) | 475 | 1.97 ± 0.07 | — | +21 | ★ |
| 48 Coq proofs, mean (2022 baseline) | — | 2.15 ± 0.13 | — | +9…+19 | >0.999 |
| Wiles FLT text (2022 baseline, outlier) | 142 | 3.39 ± 0.72 | — | +5 | ★ |
| PFR — Lean | 916 | 2.52 ± 0.28 | 0.65 | +6.5 | 1.00 |
| FLT — Lean (in progress) | 2,753 | 2.47 ± 0.22 | 0.81 | +6.6 | 0.93 |
| Sphere Packing — Lean, human-led | 1,062 | 2.97 ± 0.40 | 0.75 | +6.5 | 1.00 |
| ET — human stratum | 2,276 | 2.52 ± 0.17 | 0.79 | +7.1 | — |
| PFR — blueprint | 217 | 3.43 ± 0.54 | 0.59 | +5.6 | 0.99 |
| FLT — blueprint | 72 | 3.28 ± 0.72 | 0.75 | +2.8 | 0.91 |
| Sphere Packing — blueprint | 139 | 4.64 ± 1.15 | 0.67 | +3.9 | 0.97 |
| ET — blueprint | 115 | 2.41 ± 0.31 | 0.59 | +3.1 | 0.85 |
| Sphere Packing — Math Inc, AI-completed | 6,978 | 2.51 ± 0.11 | 0.75 | +9.0 | — |
| … Dim24 subtree (pure Gauss output) | 4,311 of 4,679 | 2.55 ± 0.14 | — | — | — |
| ET — machine stratum | 656 of 13,527 | (95% edgeless) | 0.65 | +8.3 | — |
| ET — whole graph | 15,552 | 2.14 ± 0.10 | 0.53 | +3.5 | 0.85 |
Three readings of the table. First, the 2022 universality is not a human quirk: it re-appears in
every corpus built by incremental, context-bounded construction — including the 2026 AI autoformalizer.
Second, it is not a machine inevitability either: saturation provers and brute-force enumeration,
which find each proof independently by global search, produce a topology unlike anything in the 2022
dataset — not a longer chain, not a flatter tree, but dust plus a few enormous definitional stars.
Third, the one machine method with real internal structure (MagmaEgg, greedy constructions
compiled from a human-designed metatheory, mean internal out-degree 4.4) shows the divide is not
human-vs-machine but constructed-vs-found.
Every connected network still supports an EPT, and every one still has firewalls (ΔL₁ ≈ +3 to +10, within the 2022 range). But in the machine stratum the basis of certainty has changed. A Vampire certificate is an island: no sibling paths, no re-enforcement, no abductive flow from things it enables — because it enables nothing. Its truth is pinned by exactly two things: the kernel check (in the model, an external field applied node-by-node, not a network effect) and the shared definitions it instantiates. All epistemic risk therefore concentrates in the definitional hubs — which is Commelin's "ceci n'est pas une pipe" worry (are the definitions about what we think they are?) made quantitative. A single mis-stated definition in ET touches up to 13,816 dependent results; nothing in the certificate layer could detect it, since certificates never cross-check each other. The firewall structure that lets human mathematics contain error is, in the certificate layer, replaced by a monoculture root.
The 2022 results bundle several structural properties together: heavy-tailed re-use (the α ≈ 2
degree law), modular organization (Q), and hierarchical acyclicity (proofs form a DAG). Which of
these does each phenomenon actually depend on? We ran identical belief dynamics on the real PFR
kernel network and on four randomized controls, each destroying some properties while preserving
others (results/null_models.json). The quantities compared:
| Graph | Degree sequence (α) | Q | εc | Max slope | ΔL₁ firewall |
|---|---|---|---|---|---|
| Real PFR (kernel) | real (α = 2.46) | 0.61 | 0.33 | 1.32 | +10.7 |
| Within-module rewire — scrambles wiring inside each module | real (α = 2.46) | 0.60 | 0.33 | 1.22 | +11.7 |
| Global rewire — scrambles all wiring, keeps only degrees | real (α = 2.46) | 0.27 | 0.33 | 1.16 | +6.0 |
| DAG-respecting rematch — random rewiring constrained to stay acyclic | ≈real (α = 2.20) | 0.75 | 0.33 | 1.15 | +12.3 |
| Erdős–Rényi — same node and edge counts, uniform random placement | Poisson (no hubs, no α) | 0.28 | 0.44 | (sharp step) | +5.5 |
The decomposition is clean, with one correction found by extending the ε grid past 0.40 (an earlier version of this section, computed on ε ≤ 0.40, misread the Erdős–Rényi control — its transition sits just outside that window). The belief curve is a degree-sequence phenomenon: every control that keeps the real degrees reproduces the real curve exactly, whether or not modularity or acyclicity survive. The Erdős–Rényi graph behaves qualitatively differently — but not by blurring the transition. It has a sharper, classic collective transition at ε ≈ 0.44: fully uncertain above it (m ≈ 0.01 at ε = 0.46), then everything orders at once. The real network instead orders in stages: at ε = 0.46, where the ER graph is still noise, the real network's hub core has already reached m = 0.32, and mean belief then climbs gradually as the sparse periphery melts in over a wide ε band. Heavy tails do not sharpen the transition — they move the onset of certainty to far higher error rates and stage the ordering, hubs first. The firewall is a modularity phenomenon: ΔL₁ sits at +11 to +12 in every graph that retains community structure and collapses to +6 in both graphs that lose it, independent of everything else. Acyclicity, notably, is needed for neither.
Three sharper tests, replacing the eyeball criteria of εc-and-slope
(results/transition_tests_*.json):
Susceptibility and hysteresis (PFR kernel). The susceptibility χ(ε) = N·Var(m) shows no interior peak in ε ∈ [0.10, 0.46] — it rises monotonically toward ε = 0.5 — so the smooth belief curve reported above is a finite-size crossover, not a critical singularity sitting at "εc = 0.33"; that number is a crossover midpoint and should be read as such. What is sharply present is bistability: initialized all-believing vs all-doubting, the network reaches different locked states at every tested ε up to 0.46 (hysteresis gap 0.66 even there, 1.9 at ε = 0.1). The genuinely transition-like structure in a real proof network at realistic error rates is this memory — belief and disbelief are both self-sustaining phases, and the prior decides which basin you land in. On subsampled networks of growing size the maximum slope of the belief curve grows (3.0 → 3.3 → 5.1 from N = 225 to 23k), consistent with a true singular transition emerging in the large-N limit, though subsampling distorts degree structure enough that we treat this as suggestive.
The causal arm: dialing α directly. The null models above hold the degree sequence fixed and vary everything else; the converse experiment generates synthetic directed graphs at matched size and density with the out-degree tail dialed through α = 1.8 → 4.0 (plus a Poisson control). The crossover location moves monotonically with tail weight, tracking the mean-field prediction that the critical coupling scales as ⟨k⟩/⟨k²⟩:
| Out-degree tail | ⟨k²⟩/⟨k⟩ | belief onset εc |
|---|---|---|
| α = 1.8 (heaviest) | 70.8 | 0.43 |
| α = 2.2 | 12.8 | 0.38 |
| α = 2.6 | 5.1 | 0.32 |
| α = 3.2 | 3.2 | 0.26 |
| α = 4.0 (lightest) | 2.7 | 0.24 |
| Poisson (no tail) | 10.6 | 0.44 |
So α causally sets where collective belief becomes possible — heavier-tailed reuse lets certainty form at higher error rates — and the Poisson control falling on the same ⟨k²⟩/⟨k⟩ curve shows the mechanism is the degree fluctuations themselves, exactly as mean-field theory predicts. The refined headline: heavy-tailed reuse does not make the transition sharper; it moves the onset of certainty earlier (higher ε), stages the ordering hub-core-first, and makes the believing core bistable-robust across essentially the whole error range.
A coupling-asymmetry sweep on the real graph completes the picture. Here the total coupling strength is held fixed while its split varies between βdep (forward: a claim aligns with its premises) and βimp (backward: a claim aligns with the results that use it). Either extreme destroys collective belief. Pure-backward (βdep = 0) leaves mean belief at 0.58. Pure-forward (βimp = 0) collapses it to 0.50 — chance — because axioms and definitions have no premises: with nothing flowing backward, the foundations feel no field at all, randomize, and inject noise into everything built on them. Mean belief peaks near the symmetric split, while belief in the final theorem keeps rising with forward weight (reaching 1.00 at roughly βdep:βimp = 3:1 at ε = 0.05). The model's reading: evidence flows forward, but foundations are stabilized by what they support — belief in the axioms is partly sustained by the coherence of their consequences.
The paper's asymmetric model, taken seriously in 2D
(results/asymmetric_2d.json). The 2022 paper's published curves set
βdep = βimp "for simplicity" and introduced the asymmetric model for one
mechanism: strong abduction should let disbelief in a consequence overwhelm the deductive evidence
for its premises. Sweeping the full (βdep, βimp) plane on the PFR kernel
network shows, first, that the simplification is harmless: an epistemic phase transition exists at
every ratio from 1:4 to 4:1, with εc drifting only from 0.32 to 0.35, and the 2D plane
is a wide plateau — belief organizes whenever both directions are nonzero and fails on both axes.
Second, the refutation mechanism is real but gated by redundancy: clamping the network's
most-reused node to false moves its premises by exactly nothing at any ratio — a premise's
abductive support sums over all its consequences, and one refuted child among hundreds of believed
ones is outvoted. Through fragile links (premise with only 1–2 consequences; 712 such links
in PFR), doubt does propagate backward, but only once abduction dominates: mean premise drop 0.21
(max 0.79) at βimp:βdep = 4:1, versus 0.02 at the symmetric point. In
Lakatos's terms: monsters can be barred wherever a lemma is load-bearing for many results; only
claims with a single consequence are hostage to it.
Same three theorems (IMO 2024 P1, P2, P6), machine and human, plus the 2026 research corpus:
| Corpus | Theorems | Lines/thm | Named claims /100 ln | Anonymous /100 ln | % named | Case splits /100 ln | Max claim re-use |
|---|---|---|---|---|---|---|---|
| AlphaProof 2024 (raw IMO output) | 3 | 76.7 | 0.0 | 13.9 | 0% | 8.3 | 0 |
| Human expert (Myers, mathlib Archive) | 55 | 11.1 | 5.1 | 0.0 | 100% | 3.9 | 2 |
| AlphaProof Nexus 2026 (research problems) | 2,494 | 16.4 | 17.7 | 0.5 | 97% | 4.0 | 17 |
The 2024 system solved the problems and wrote them the way search trees look: one monolithic proof per
theorem, intermediate facts bound anonymously (each have: shadowing the last — literally
un-addressable), double the human case-split rate, and — as its own annotators note in the mirror repo —
"the agent wastes the next 16 lines proving then discarding a lemma." Where the human formalizer of the
same theorems produced 57 small named lemmas, AlphaProof produced 3 sealed blocks. Per the EPT model,
such a proof cannot host a phase transition for its reader: there is one path to every claim, so
doubt decays nothing and certainty comes only from the kernel.
Two years later, Nexus writes mathematics whose skeleton is indistinguishable from — indeed more
articulated than — expert human Lean: 97% of claims named (with human-readable names like
exists_separablyGenerated_charZero), naming density 3× the human expert, case-splitting at
human rates, and claims re-used up to 17 times. The obvious deflationary explanation — imitation of human
training style — is incomplete: naming density overshoots human practice substantially. The more
interesting hypothesis is that addressable, modular subgoals are instrumentally necessary for any
bounded-context agentic prover — the machine rediscovered lemma culture for the same reason
mathematicians invented it. If so, the 2022 topology is a signature of resource-rational proving as
such, and human mathematics found it first because human working memory is the tightest bound.
DeDeo & Duede's tracking condition — the formal proof should realize the informal proof's inferential
steps — becomes measurable with blueprints: for each blueprint edge whose endpoints carry
\lean{} tags, ask whether the formal graph contains a path between the tagged declarations.
Bars: share of testable informal dependency edges realized as formal paths (≤ 6 hops, project-internal). Textual extraction under-counts, so read the gradient, not the levels — kernel-grain validation on compiled PFR raises its level from 74% to 86% (direct edges 50% → 65%), leaving the gradient intact.
The gradient tracks machine involvement. PFR — the disciplined human speedrun where the blueprint was the coordination instrument — realizes three-quarters of its informal edges formally, at a resolution ratio of 4.6 formal declarations per informal statement. ET realizes barely a third, at a ratio of 80:1: the blueprint narrates the human-facing theory while the 22M-edge machine payload lives entirely outside the narrative. The same holds for representational churn: only 213 of the human repo's 816 declaration names survive in Math Inc's AI-completed sphere-packing repo. Formal mathematics is becoming a medium in which the informal account is one projection of a much larger object it only partially tracks — the Standard View's "corresponding derivation" increasingly corresponds to nothing a human wrote.
The strongest cross-cutting regularity in the new data: every corpus produced by incremental construction under bounded context — Greek deduction, Coq libraries, human Lean, agentic AI — lands on α ≈ 2 with strong modularity; every corpus produced by global search or enumeration lands off it, in dust or stars. This reframes the 2022 universality as resource-rationality, converges with the "tinkering/reuse" generative model there, and explains the AI style transition of §5 without invoking taste: naming and modularity are what proving under a context window forces on any agent. It also predicts where AlephZero-style systems will and won't produce human-legible mathematics: legibility tracks the generator's boundedness, not its carbon.
The kernel check acts as a per-node external field: it can pin any node to "true" regardless of network support. The machine stratum shows what mathematics looks like when only the field remains — verified, believed, and structurally incapable of being understood through path-multiplicity, because the paths don't exist. Duede & Davey's warrant-without-surveyability, Avigad's understanding-as-abilities, and Tao's "proof by intimidation" worry are all statements about this decoupling; the network model gives it an order parameter (field-pinned belief vs. coherence-supported belief) and the ET data gives it an existence proof at 22-million-edge scale.
When certificates share nothing but definitions, definitions inherit all systemic risk (§4) — the network-theoretic form of AlephZero's aboutness problem and of the LTE test-suite practice. Prediction: the load-bearing artifact of AI-era mathematics is not the proof but the definition-plus-test-suite, and "stress-testing definitions" will professionalize the way refereeing once did (the Sphere-Packing team's language is already there).
Blueprints are simultaneously: the community's shared mental model (Wiles-signature topology, written for communication), the coordination contract for strangers and machines (Habgood-Coote & Tanswell's group knowledge, executable), and the empirical interface where correspondence is negotiated (§6). They are hand-authored EPT networks with per-node formalization state and git timestamps — the richest belief-formation dataset the field has ever produced, and nobody has analyzed them dynamically yet.
α ≈ 2 + Q ≳ 0.6 emerges in any proof corpus whose generator has bounded working context and pays a cost for re-derivation; global-search generators produce α < 1.7 (stars) or no fit (dust).
Ablate context length in an open prover (Goedel-Prover-V2, DeepSeek-Prover) on a fixed theorem set; measure α, naming density, and modularity of the output corpus as functions of window size.
For the same mathematics, αcommunication > αverification; the gap Δα measures how much shared background the community's discourse presupposes (Euclid's text, unusually explicit, had Δα ≈ 0; modern blueprints have Δα ≈ 1–2.7).
Compute Δα across the ~40 leanblueprint projects; correlate with community size, field maturity, and formalization speed. Prediction: Δα shrinks as autoformalization becomes the medium of record, because the formal object starts being the communication.
As machine-generated proof mass grows, epistemic load (betweenness, out-degree share) concentrates on definitional nodes; ecosystem failure modes shift from wrong-step to wrong-aboutness.
Longitudinal Gini of out-degree over mathlib/ETP git history; count historical incidents (quadratic-reciprocity-with-no-primes style) per era; measure test-suite-to-definition ratios as the adaptive response.
Field-pinned (verified, structureless) results accumulate as a stratum that is believed but never re-used — operationalizing "zombie mathematics." Re-use, not verification, predicts downstream value.
Already visible: 35 of 22,062 ET edges flow machine→human. Track five years of citation/ re-use flow into AI-proved results (Nexus's Erdős corpus is the natural cohort) vs. matched human results.
Agentic provers name and modularize because addressable subgoals are required for search under bounded context — not (only) because training data looks that way. Naming density should therefore track the agent's decomposition depth, not its training corpus style.
Compare naming density across systems with similar training data but different architectures (whole-proof RL vs. subgoal-decomposition vs. agentic-loop); the 2024→2026 overshoot (0 → 17.7 per 100 lines, 3× human) is initial evidence.
Fluent AI arguments raise abductive confidence without adding deductive paths. The 2022 model predicts over-weighted abduction lowers attainable certainty — so communities exposed to plausible unverified AI proofs should rationally increase demand for formal checking, not decrease it.
The Leiden Declaration and the verification-first norms of 2025–26 are the predicted response. Measurable: referee checking budgets and formalization-before-announcement rates, pre/post 2024.
Copilots eliminate local impasses; definitional adequacy and value selection remain. Time-at-impasse distributions shift from heavy-tailed to bimodal (instant or intractable), hollowing out the middle difficulty band where, per AlephZero, judgements of value are trained.
Lean interaction telemetry (time-between-tactics, sorry lifetimes in git) across cohorts with/without AI assistance; blueprint git histories give sorry-lifetime distributions back to 2021.
Blueprint-engineered modularity yields the same ΔL₁ containment as evolved modularity (confirmed here: +3 to +10 across both), but relocates trust to interfaces: type signatures become the contract, and interface errors — not interior errors — become the dominant failure class.
Classify historical formalization bugs (mathlib issues, LTE/Sphere errata, Gauss's two caught source errors) as interior vs. interface/definitional; the model predicts a rising interface share.
\leanok flip is a timestamped
belief-state change on a known network. Fit the Ising dynamics to the actual percolation of formalization
across PFR/FLT/Sphere/Carleson; test whether progress cascades from high-out-degree nodes as the model
predicts. This is the first chance to test the 2022 dynamics, not just its statics.\uses edges are author-curated and sparser than actual dependence; the Wiles-like
α may partly reflect curation. (So did Wiles's own citations — that is the point.)Anchor papers: Viteri & DeDeo, Cognition 225:105120 (2022) + appendix ·
DeDeo, Bull. AMS 61:375 (2024) · DeDeo & Duede, arXiv:2603.13680 (2026).
Data (all public, re-extracted here):
teorth/pfr ·
teorth/equational_theories ·
ImperialCollegeLondon/FLT ·
Sphere-Packing-Lean (human-led) ·
math-inc/Sphere-Packing-Lean ·
AlphaProof IMO 2024 raw outputs ·
AlphaProof Nexus results ·
compfiles (human IMO formalizations).
Context: ETP paper arXiv:2512.07087 · AlphaProof, Nature (2025) · Avigad, "Mathematicians in
the age of AI," arXiv:2603.03684 · Tao, "Machine-Assisted Proof," Notices AMS 72(1) ·
Venkatesh, "Human Mathematics in the Age of Reasoning Machines" (2025) · Duede & Davey,
Phil. Sci. (2025) · Leiden Declaration (2026) · mathlib network studies: arXiv:2604.24797,
proofgraph.org · ProofOptimizer, arXiv:2510.15700 · Vampire-on-ETP, arXiv:2508.15856.