erdos_12.parts.ii.lean`

Explanation legend Lean4 Domain Explanation Language (L4DEL)

L4DEL explanations are a separate layer. They do not change the Lean source. Intuition is explanatory prose; numbered items are a reading path; sources link the wording back to evidence.

L4DEL: Lean4 Domain Explanation Language

Annotation provenance. This overlay contains 348 curated AI-written annotations and 373 mechanical source-derived annotations. They have not been human-reviewed as explanations; treat them as unverified and not mathematical authority. Retained generation history: The 12 manuscript-grounded curated result annotations were composed from pinned companion PDFs and named source records in a Codex session on 2026-10-14; no human review is claimed, and the exact runtime model identifier was not exposed to the artifact generator. Twelve supporting declarations for the Hilbert-functions result were upgraded on 2026-10-14 from mechanically condensed doc comments to declaration-specific explanations bound to exact page-one terminology in the pinned human-written companion. The other Hilbert challenge statements were deliberately not described as companion-backed results because that manuscript proves P5 specifically. Fifteen previously unannotated declarations along the Hilbert P5 proof spine were annotated on 2026-10-14 from the pinned companion's seven-page argument, covering the two-generator decomposition, finite-difference bounds, critical-case reduction, and final log-concavity step. Each quotation is bound to its exact manuscript page and Lean declaration; no human review is claimed. Twenty-four further declarations along the Hilbert P5 box-count and finite-difference spine were annotated on 2026-10-14, covering the two-dimensional slice count, three-dimensional box formula, first- and second-difference identities, the seven-threshold curvature expression, boundary handling, pointwise transport, sum linearity, and lower-or-upper region classification. Every annotation is bound to an exact quotation on pages 2 or 3 of the pinned human-written companion; Lean-specific boundary and threshold helpers are identified as implementation lemmas rather than separate manuscript claims. No human review is claimed. Twenty-eight further declarations along the Hilbert P5 argument were annotated on 2026-10-14 from pages 2 through 6 of the pinned human-written companion. They expose the shifted residual sequence, exact lower- and upper-region formulas, symmetry by complementary divisors, the curvature-one and curvature-two splits, and the final algebraic reductions. Lean-only transport and integer-arithmetic helpers are labeled as proof infrastructure rather than new manuscript claims; each quotation is page-bound in the source ledger, and no human review is claimed. Twenty high-level declarations completing the Hilbert P5 curvature-one and curvature-two case spine were annotated on 2026-10-14 from pages 3 through 7 of the pinned human-written companion. The explanations separate cases A and B, lower and upper monomial regions, shifted residual evaluation, impossible mixed regions, and the surviving upper-upper estimate; wrapper lemmas are explicitly described as proof structure. Every quotation is page-bound, and no human review is claimed. Twenty-two graph-reconstruction declarations were upgraded or added on 2026-10-14 from the pinned four-page human-written companion, covering the incidence-deletion deck, edge and degree recovery, unique isolated vertices, vertex-type reconstruction, neighboring-type descent, adjacency recovery, and final bipartite isomorphism. The result annotation also records that `G_not_regular` is present in the Lean statement but unused by its proof term and absent from the companion theorem. Exact historical quotations from Paul J. Kelly (1957) and Bondy with Hemminger (1977) are linked separately; no human review is claimed. Eighteen declarations along the Erdős 741(i) strict-natural-density counterexample were added on 2026-10-14, covering the carry-free base-four digit split, full cross-sum coverage, sparse pure self-sums, fixed-factor fat intervals, the lower-scale density deficit, upper-scale sum growth, and the final convergence contradiction. The result annotation was corrected to distinguish the negative strict-natural-density Lean theorem from the compatible affirmative upper-density companion theorem; Ulam AI's written counterexample is explicitly identified as using a different interval length with the same mechanism. The quotations are page- and hash-bound where the PDFs expose text; Paul Erdős's scanned 1994 question was visually checked and is linked separately without a machine-audit claim. No human review is claimed. Twenty-eight additional declaration-level annotations were added on 2026-10-14 for the Erdős 12(i) proof, and its IsGood definition was upgraded from a source-comment condensation. They cover the prime and Chinese-remainder moduli, the actual Lean congruence-block witness, exclusion of cross-block and same-block triples, lower and upper counting bounds, and the positive liminf. The prior result annotation was corrected because the pinned human-written companion proves the same theorem with a different base-2-to-base-3 construction; it is no longer presented as the Lean proof. The original property-P definition from Erdős and Sárközy (1970) is separately linked and page-bound; no human review is claimed. The remaining fifty declarations in the Erdős 12(i) file were annotated on 2026-10-14, completing declaration-level coverage of all eighty definitions, lemmas, and theorems in that file. These additions expose the prime-recursion invariants, divisibility transport, Chinese-remainder witness bounds, numerical density envelopes, injective block coding, and liminf support lemmas instead of leaving the proof spine as raw Lean; no human review is claimed. Eighteen supporting declarations for Erdős 125 were added on 2026-10-14, completing all nineteen declarations in the file. The annotations follow the pinned companion through digit-block decomposition, irrational logarithmic approximation, the explicit Lean contraction factor 11/12, geometric iteration, and the lower-density conclusion. The original 1996 question of Burr, Erdős, Graham, and Li and the 2026 discussion contributions of GTSoukalas, Terence Tao, and Giuseppe Melfi are linked separately; no human review is claimed. Twenty-eight supporting declarations for Erdős 138 were upgraded or added on 2026-10-14, completing all twenty-nine declarations in the file. The annotations separate the greedy difference proof from the Lean-specific representation bridges and ultrafilter compactness proof of existence, and bind quotations from the pinned companion, the AlphaProof Nexus paper, Erdős's 1981 source, van der Waerden's recollection, and the 2026 Erdős Problems discussion. No human review is claimed. The curated Erdős 12(ii), 138, and 152 annotations were further linked on 2026-10-14 to exact quotations from Felix Behrend, Bartel van der Waerden, and Paul Erdős with Pál Turán; the historical quotation sources are labeled separately from the pinned AlphaProof proof companions. The curated Hilbert-functions result, its OrderIdeal and pureOSequence definitions, and the Erdős 846 annotation were further linked on 2026-10-14 to exact quotations from Richard P. Stanley and from Moe Putterman, Mehtaab Sawhney, and Gregory Valiant. The Stanley PDF is hash- and page-bound in the source ledger; these historical sources are labeled separately from the pinned AlphaProof proof companions. Three additional target-specific annotations for Ben Green's Problem 57, exact last-iterate anchored-GDA convergence, and Graffiti.pc Conjecture 2 were composed on 2026-10-14 from the exact pinned Lean statements, quotations from the AlphaProof Nexus paper, and quotations from Green, Ryu with Yuan and Yin, Surina et al., and Wang with Dai and Tong; no human review is claimed. Two additional target-specific quantum-optics annotations for the explicit AME(11,5) construction and the even N >= 4, D = N monochromatic-quantum-graph theorem were composed on 2026-10-14 from the exact pinned Lean statements, page-bound quotations from the AlphaProof Nexus paper, Helwig et al., and Krenn, Gu, and Zeilinger, and Mario Krenn's public priority correction. The AME annotation makes no first-discovery claim; the monochromatic annotation states that the local AlphaProof wrapper contains sorry and links the separate pinned proof-bearing Formal Conjectures artifact without silently treating it as local verification. Twelve declarations that the pinned source repeats verbatim in several files were annotated in only one of the copies, so the build rejected them as differing copies. On 2026-10-16 each curated annotation was copied unchanged to every identical copy: the eleven Hilbert-functions definitions from hilbert_functions_5 to hilbert_functions_1, _2, _3, _4, _7 and _8, and Erdos12.IsGood from erdos_12.parts.i to erdos_12.parts.ii (the better-sourced annotation was kept in each case). Each copy's quotations are bound in the source ledger like the original's; no new text was written and no human review is claimed. The remaining source-derived annotations were generated mechanically from pinned source comments by tooling developed in a GPT-5.6 Sol session at ultra reasoning; GPT-5.6 Sol did not originate the source prose.

Credit: Google DeepMind published the AlphaProof Nexus proof artifacts. The pinned repository identifies the mathematical sources and collaborators, including OEIS, Erdős Problems, Gergely Bérczi, and Mario Krenn; those source records remain the authority for individual credit.

Project sources: Pinned AlphaProof Nexus results documentation, AlphaProof Nexus paper, Pinned human-written natural-language proof companions

32 declarations, 0 contain sorry, 0 declared as axioms

Imports (1)

FormalConjectures.Util.ProblemImports

abbrev Erdos12.IsGood Property P: no member divides the sum of two larger distinct members line 48 source
Source documentation
A set A is "good" if it is infinite and there are no distinct a,b,c in A such that a ∣ (b+c) and b > a, c > a.
L4DEL explanation
divides the sum of two larger terms
— Paul Erdős and András Sárközy (1970), p. 97
IsGood A means that A is infinite and whenever a,b,c ∈ A, a ∣ b+c, a<b, and a<c, the two larger terms must coincide. Equivalently, no three distinct members realize the forbidden divisibility pattern.
1. The conclusion b = c is how the Lean predicate permits repeated use of one larger element while excluding a triple of distinct elements.
2. This is the formal version of the property introduced by Paul Erdős and András Sárközy; their ordered-sequence wording and the set-based Lean wording express the same restriction.
Sources and attribution: Pinned Lean source (0647711a7118), Paul Erdős and András Sárközy (1970), p. 97
no axioms what this means
Statement uses: Set, Nat
Proof uses: And, Set.Infinite, Membership.mem, Dvd.dvd, HAdd.hAdd, LT.lt, Eq
5 instances, coercions and auxiliary constants left out.

Also declared: APNOutputs/ErdosProblems/erdos_12.parts.i.lean:48 (same declaration text).
```
abbrev IsGood (A : Set ℕ) : Prop := A.Infinite ∧
…
```
lemma Erdos12.not_infinite_iff_eventually line 90 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Nat, Iff, Not, Set.Infinite, setOf, Filter.Eventually, Filter.atTop
Proof uses: Eq.mpr, Set.Finite, id, Eq, congrArg, propext, Set.not_infinite, Exists, GE.ge, Filter.eventually_atTop, Iff.intro, BddAbove, Set.Finite.bddAbove, Membership.mem, Set, upperBounds, Exists.intro, HAdd.hAdd, OfNat.ofNat, LE.le and 5 more
27 instances, coercions and auxiliary constants left out.

Tactic trace: 22 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.sarkozy_case_same line 112 source
standard axioms: Quot.sound, propext what this means
Statement uses: Nat, LT.lt, HAdd.hAdd, HMul.hMul, OfNat.ofNat, Dvd.dvd, False
Proof uses: Eq, Eq.mp, congrArg, Nat.mul_comm, GT.gt, Decidable.byContradiction, Not, GE.ge, LE.le, Nat.mul_le_mul_right
22 instances, coercions and auxiliary constants left out.

Tactic trace: 14 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.sarkozy_case_diff2 line 126 source
standard axioms: Quot.sound, propext what this means
Statement uses: Nat, GT.gt, OfNat.ofNat, Eq, HMod.hMod, Dvd.dvd, HAdd.hAdd, False
Proof uses: Nat.dvd_of_mod_eq_zero, dvd_trans, Nat.mod_eq_zero_of_dvd, Eq.symm, Nat.add_mod, Eq.mp, congrArg, Nat.mod_eq_of_lt
16 instances, coercions and auxiliary constants left out.

Tactic trace: 8 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.sarkozy_case_diff1 line 136 source
standard axioms: Quot.sound, propext what this means
Statement uses: Nat, GT.gt, OfNat.ofNat, Eq, HMod.hMod, Dvd.dvd, HAdd.hAdd, False
Proof uses: Nat.dvd_of_mod_eq_zero, dvd_trans, Nat.mod_eq_zero_of_dvd, Eq.symm, Nat.add_mod, Eq.mp, congrArg, Decidable.byContradiction, Not, Nat.mod_eq_of_lt
18 instances, coercions and auxiliary constants left out.

Tactic trace: 10 steps
Open to load the checked before-and-after goal states.
def Erdos12.IsGoodSarkozySeq line 147 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Nat, Set, Real
Proof uses: And, Membership.mem, Eq, HMod.hMod, OfNat.ofNat, GT.gt, LT.lt, HAdd.hAdd, HMul.hMul, Set.Infinite, Set.iUnion, Filter.Eventually, LE.le, HPow.hPow, HSub.hSub, Set.ncard, Inter.inter, Set.Icc, Filter.atTop
20 instances, coercions and auxiliary constants left out.
lemma Erdos12.sarkozy_implies_good line 156 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Nat, Set, Real, Erdos12.IsGoodSarkozySeq, Erdos12.IsGood, Set.iUnion
Proof uses: Membership.mem, Eq, HMod.hMod, OfNat.ofNat, And, GT.gt, LT.lt, HAdd.hAdd, HMul.hMul, Set.Infinite, Filter.Eventually, LE.le, HPow.hPow, HSub.hSub, Set.ncard, Inter.inter, Set.Icc, Filter.atTop, And.intro, Dvd.dvd and 17 more
36 instances, coercions and auxiliary constants left out.

Tactic trace: 61 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.sarkozy_seq_of_aux line 211 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Nat, Set, Real, Membership.mem, Eq, HMod.hMod, OfNat.ofNat, GT.gt, LT.lt, GE.ge, HMul.hMul, LE.le, Set.Infinite, Set.iUnion, Filter.Eventually, HPow.hPow, HSub.hSub, Set.ncard, Inter.inter, Set.Icc and 2 more
Proof uses: And.intro, And, HAdd.hAdd, Decidable.byContradiction, Not
43 instances, coercions and auxiliary constants left out.

Tactic trace: 33 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.sarkozy_primes line 243 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Exists, Nat, And, GT.gt, OfNat.ofNat, LT.lt, Ne, Nat.Prime, LE.le, HPow.hPow, HAdd.hAdd
Proof uses: HMul.hMul, Exists.intro, And.intro, LT.lt.trans_le', And.left, And.right, Bound.le_self_pow_of_pos, Mathlib.Meta.NormNum.isNat_le_true, Mathlib.Meta.NormNum.isNat_ofNat, Eq.refl, Bool, Bool.true, Nat.zero_lt_succ, LT.lt.ne, LE.le.trans_lt, Eq.rec, Nat.succ, Eq, lt_of_le_of_lt, pow_right_monotone and 29 more
45 instances, coercions and auxiliary constants left out.

Tactic trace: 7 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.mod_eq_of_mod_mul line 247 source
standard axioms: propext what this means
Statement uses: Nat, Eq, HMod.hMod, OfNat.ofNat
Proof uses: Dvd.dvd, Nat.dvd_of_mod_eq_zero, Nat.ModEq.of_dvd
7 instances, coercions and auxiliary constants left out.

Tactic trace: 2 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.sarkozy_CRT_single line 252 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Nat, Nat.Prime, LT.lt, Ne, Exists, And, Eq, HMod.hMod, OfNat.ofNat
Proof uses: Finset.prod, Finset.range, Nat.Coprime, Nat.Coprime.prod_right, Membership.mem, Finset, Ne.symm, Eq.mp, congrArg, propext, Finset.mem_range, Iff.mpr, Nat.coprime_primes, Subtype, Nat.ModEq, Nat.chineseRemainder, Exists.intro, And.intro, And.left, Subtype.property and 11 more
12 instances, coercions and auxiliary constants left out.

Tactic trace: 31 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.sarkozy_CRT line 284 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Nat, Nat.Prime, LT.lt, Ne, Exists, And, Eq, HMod.hMod, OfNat.ofNat
Proof uses: Erdos12.sarkozy_CRT_single, Exists.intro, Classical.choose, Classical.choose_spec
8 instances, coercions and auxiliary constants left out.

Tactic trace: 4 steps
Open to load the checked before-and-after goal states.
def Erdos12.P_n_def line 291 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Nat
Proof uses: HMul.hMul, Finset.prod, Finset.range
3 instances, coercions and auxiliary constants left out.
lemma Erdos12.P_n_mod_pn line 293 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Nat, Eq, HMod.hMod, Erdos12.P_n_def, OfNat.ofNat
Proof uses: Dvd.dvd, Eq.mpr, HMul.hMul, Finset.prod, Finset.range, id, congrArg, Erdos12.P_n_def.eq_1, Nat.dvd_mul_right, Nat.mod_eq_zero_of_dvd
7 instances, coercions and auxiliary constants left out.

Tactic trace: 4 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.P_n_mod_pm line 299 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Nat, LT.lt, Eq, HMod.hMod, Erdos12.P_n_def, OfNat.ofNat
Proof uses: Dvd.dvd, Eq.mpr, HMul.hMul, Finset.prod, Finset.range, id, congrArg, Erdos12.P_n_def.eq_1, Finset.dvd_prod_of_mem, Membership.mem, Finset, propext, Finset.mem_range, dvd_mul_of_dvd_right, Nat.mod_eq_zero_of_dvd
11 instances, coercions and auxiliary constants left out.

Tactic trace: 8 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.P_n_def_pos line 309 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Nat, GT.gt, OfNat.ofNat, Erdos12.P_n_def
Proof uses: Decidable.byContradiction, Not, Finset.prod, Finset.range, Finset.prod_pos, Membership.mem, Finset, LT.lt, Eq.mpr, HMul.hMul, id, Eq, congrArg, Erdos12.P_n_def.eq_1, Nat.mul_pos
24 instances, coercions and auxiliary constants left out.

Tactic trace: 10 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.M_n_growth line 321 source
standard axioms: Quot.sound, propext what this means
Statement uses: Nat, LT.lt, HMul.hMul, OfNat.ofNat, HAdd.hAdd, GE.ge
Proof uses: Nat.recAux, Nat.zero_le, LE.le, Decidable.byContradiction, Not
17 instances, coercions and auxiliary constants left out.

Tactic trace: 6 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.B_n_props line 329 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Nat, Eq, HMod.hMod, OfNat.ofNat, LT.lt, Set, setOf, And, Membership.mem, Set.Icc, HMul.hMul, Erdos12.P_n_def, GE.ge, LE.le
Proof uses: And.intro, And.right, Erdos12.P_n_mod_pn, Erdos12.mod_eq_of_mod_mul, Eq.mp, congrArg, Erdos12.P_n_mod_pm, And.left
19 instances, coercions and auxiliary constants left out.

Tactic trace: 27 steps
Open to load the checked before-and-after goal states.
def Erdos12.ValidMSeq line 359 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Real, Nat
Proof uses: And, GE.ge, OfNat.ofNat, LT.lt, HMul.hMul, HAdd.hAdd, Erdos12.P_n_def, LE.le, HPow.hPow, HSub.hSub, HDiv.hDiv
23 instances, coercions and auxiliary constants left out.
lemma Erdos12.valid_M_seq_gap line 365 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Real, Nat, Erdos12.ValidMSeq, LT.lt, HMul.hMul, OfNat.ofNat
Proof uses: Nat.recAux, Decidable.byContradiction, Not, HAdd.hAdd, Or, Eq, Eq.mpr, id, congrArg, And.left, And, GE.ge, Erdos12.P_n_def, LE.le, HPow.hPow, HSub.hSub, HDiv.hDiv, And.right
34 instances, coercions and auxiliary constants left out.

Tactic trace: 12 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.prod_p_bound line 377 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Nat, LE.le, HPow.hPow, OfNat.ofNat, HAdd.hAdd, Finset.prod, Finset.range
Proof uses: Nat.recAux, of_eq_true, Eq.trans, True, congrArg, zero_add, one_pow, pow_one, Eq.mpr, HMul.hMul, id, Eq, Finset.prod_range_succ, Nat.mul_le_mul, Eq.symm, Nat.pow_add, Mathlib.Tactic.Ring.of_eq, Nat.rawCast, Mathlib.Tactic.Ring.instCommSemiringNat, Mathlib.Tactic.Ring.add_congr and 83 more
112 instances, coercions and auxiliary constants left out.

Tactic trace: 20 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.P_n_bound line 397 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Nat, LE.le, HPow.hPow, OfNat.ofNat, HAdd.hAdd, Erdos12.P_n_def
Proof uses: Eq.mpr, HMul.hMul, Finset.prod, Finset.range, id, Eq, congrArg, Erdos12.P_n_def.eq_1, Erdos12.prod_p_bound, Nat.mul_le_mul, Eq.symm, Nat.pow_add, Eq.refl, Mathlib.Tactic.Ring.of_eq, Nat.rawCast, Mathlib.Tactic.Ring.instCommSemiringNat, Mathlib.Tactic.Ring.add_congr, Mathlib.Tactic.Ring.atom_pf, Mathlib.Tactic.Ring.cast_pos, Mathlib.Meta.NormNum.isNat_ofNat and 80 more
94 instances, coercions and auxiliary constants left out.

Tactic trace: 16 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.exponent_bound line 412 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Real, GT.gt, OfNat.ofNat, LT.lt, GE.ge, HMul.hMul, Nat, LE.le, HAdd.hAdd, HPow.hPow, HSub.hSub
Proof uses: le_of_not_gt, Mathlib.Tactic.Linarith.lt_irrefl, Eq.mp, congrArg, Mathlib.Tactic.Ring.of_eq, Mathlib.Tactic.Ring.add_congr, Nat.rawCast, Mathlib.Tactic.Ring.instCommSemiringNat, Int.rawCast, Int.negOfNat, Mathlib.Tactic.Ring.sub_congr, Mathlib.Tactic.Ring.cast_pos, Mathlib.Meta.NormNum.isNat_ofNat, Eq.refl, Mathlib.Meta.NormNum.instAtLeastTwo, Mathlib.Tactic.Ring.mul_congr, Mathlib.Tactic.Ring.atom_pf, Mathlib.Tactic.Ring.add_mul, Mathlib.Tactic.Ring.mul_add, Mathlib.Tactic.Ring.mul_pf_left and 62 more
107 instances, coercions and auxiliary constants left out.

Tactic trace: 11 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.exists_valid_M_seq line 421 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Real, GT.gt, OfNat.ofNat, LT.lt, Nat, LE.le, HPow.hPow, HAdd.hAdd, Exists, Erdos12.ValidMSeq
Proof uses: Nat.ceil, HDiv.hDiv, HMul.hMul, Exists.intro, GE.ge, Eq.mpr, id, Eq, congrArg, propext, lt_div_iff₀, lt_of_not_ge, Mathlib.Tactic.Linarith.lt_irrefl, Eq.mp, HSub.hSub, Mathlib.Tactic.Ring.of_eq, Mathlib.Tactic.Ring.add_congr, Int.rawCast, Int.negOfNat, Nat.rawCast and 165 more
216 instances, coercions and auxiliary constants left out.

Tactic trace: 196 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.B_seq_infinite line 574 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Nat, Set, LT.lt, HMul.hMul, OfNat.ofNat, HAdd.hAdd, HasSubset.Subset, Set.Icc, Set.Nonempty, Set.Infinite, Set.iUnion
Proof uses: Set.infinite_of_forall_exists_gt, Membership.mem, Exists, And, Exists.intro, GE.ge, And.left, LE.le, Erdos12.M_n_growth, GT.gt, Decidable.byContradiction, Not, And.intro, Eq.mpr, id, Eq, congrArg, propext, Set.mem_iUnion
25 instances, coercions and auxiliary constants left out.

Tactic trace: 17 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.B_seq_nonempty line 590 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Nat, GE.ge, HMul.hMul, OfNat.ofNat, Erdos12.P_n_def, GT.gt, Set.Nonempty, setOf, And, Membership.mem, Set, Set.Icc, Eq, HMod.hMod
Proof uses: HSub.hSub, HAdd.hAdd, LT.lt, Nat.mod_lt, LE.le, Nat.le_add_right, Nat.add_lt_add_left, Nat.add_le_add_left, Mathlib.Tactic.Ring.of_eq, HPow.hPow, Nat.rawCast, Mathlib.Tactic.Ring.instCommSemiringNat, Mathlib.Tactic.Ring.add_congr, Mathlib.Tactic.Ring.mul_congr, Mathlib.Tactic.Ring.cast_pos, Mathlib.Meta.NormNum.isNat_ofNat, Eq.refl, Mathlib.Tactic.Ring.atom_pf, Mathlib.Tactic.Ring.add_mul, Mathlib.Tactic.Ring.mul_add and 26 more
44 instances, coercions and auxiliary constants left out.

Tactic trace: 25 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.B_seq_ncard line 623 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Nat, GE.ge, HMul.hMul, OfNat.ofNat, Erdos12.P_n_def, GT.gt, LE.le, Real, HSub.hSub, HDiv.hDiv, Set.ncard, setOf, And, Membership.mem, Set, Set.Icc, Eq, HMod.hMod
Proof uses: Trans.simple, Finset.card, Finset.image, HAdd.hAdd, Finset.range, Iff.mpr, sub_le_iff_le_add, div_le_iff₀', Mathlib.Tactic.Bound.Nat.cast_pos_of_pos, cast, Eq.symm, Eq.trans, congrArg, Nat.cast_one, congr, le_of_lt, of_eq_true, LT.lt, True, funext and 93 more
190 instances, coercions and auxiliary constants left out.

Tactic trace: 26 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.exists_M_n_and_B_n line 637 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Real, GT.gt, OfNat.ofNat, LT.lt, Nat, LE.le, HPow.hPow, HAdd.hAdd, Eq, HMod.hMod, Exists, Set, And, setOf, Membership.mem, Set.Icc, HMul.hMul, Erdos12.P_n_def, Set.Infinite, Set.iUnion and 5 more
Proof uses: Erdos12.ValidMSeq, Erdos12.exists_valid_M_seq, Exists.intro, And.intro, Eq.refl, Erdos12.valid_M_seq_gap, And.left, GE.ge, HDiv.hDiv, And.right, HasSubset.Subset, Set.Nonempty, Erdos12.P_n_def_pos, Erdos12.B_seq_nonempty, Erdos12.B_seq_infinite, Eq.mpr, id, congrArg, propext, Filter.eventually_atTop and 117 more
184 instances, coercions and auxiliary constants left out.

Tactic trace: 61 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.exists_sarkozy_seq_aux line 689 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Real, GT.gt, OfNat.ofNat, LT.lt, Exists, Nat, Set, And, Membership.mem, Eq, HMod.hMod, GE.ge, HMul.hMul, LE.le, Set.Infinite, Set.iUnion, Filter.Eventually, HPow.hPow, HSub.hSub, Set.ncard and 3 more
Proof uses: Erdos12.exists_sarkozy_seq_aux.match_1, Ne, Nat.Prime, HAdd.hAdd, Erdos12.sarkozy_primes, Erdos12.exists_sarkozy_seq_aux.match_2, Erdos12.sarkozy_CRT, And.left, And.right, Erdos12.exists_sarkozy_seq_aux.match_3, setOf, Erdos12.P_n_def, Erdos12.exists_M_n_and_B_n, Exists.intro, And.intro, Erdos12.B_n_props, Eq.mpr, id, congrArg, Eq.symm
48 instances, coercions and auxiliary constants left out.

Tactic trace: 55 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.exists_sarkozy_seq line 741 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Real, GT.gt, OfNat.ofNat, LT.lt, Exists, Nat, Set, Erdos12.IsGoodSarkozySeq
Proof uses: And, Membership.mem, Eq, HMod.hMod, GE.ge, HMul.hMul, LE.le, Set.Infinite, Set.iUnion, Filter.Eventually, HPow.hPow, HSub.hSub, Set.ncard, Inter.inter, Set.Icc, Filter.atTop, Erdos12.exists_sarkozy_seq_aux, Exists.intro, Erdos12.sarkozy_seq_of_aux
29 instances, coercions and auxiliary constants left out.

Tactic trace: 3 steps
Open to load the checked before-and-after goal states.
lemma Erdos12.exists_good_set_dense_c_lt_1 line 747 source
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Real, GT.gt, OfNat.ofNat, LT.lt, Exists, Set, Nat, And, Erdos12.IsGood, Not, Set.Infinite, setOf, Set.ncard, Inter.inter, Set.Icc, HPow.hPow, HSub.hSub
Proof uses: Erdos12.IsGoodSarkozySeq, Erdos12.exists_sarkozy_seq, Exists.intro, Set.iUnion, And.intro, Erdos12.sarkozy_implies_good, Iff, Filter.Eventually, Filter.atTop, Erdos12.not_infinite_iff_eventually, Eq.mpr, id, Eq, congrArg, propext, Filter.Eventually.mono, LE.le, And.right, Membership.mem, HAdd.hAdd and 4 more
43 instances, coercions and auxiliary constants left out.

Tactic trace: 11 steps
Open to load the checked before-and-after goal states.
theorem Erdos12.target_theorem_0 Erdős problem 12(ii): no universal power saving for every admissible set line 762 source
L4DEL explanation
The proof is similar to the previous one for Erdős #12(i), differing mainly in the use of a Behrend-style construction
— Human-written proof companion for Erdős 12(ii)
Let S be a set of non-negative integers < N no three of which form an arithmetical progression
— Felix Behrend (1946), original PNAS paper, p. 331
The proposed universal exponent c > 0 is false: one can construct an admissible infinite set whose counting function is at least N^(1-c) eventually for every chosen positive c. The theorem packages that negative answer as the failure of the asserted uniform sparse-subsequence bound.
1. A Behrend-style sphere supplies dense finite sets with no three-term arithmetic progression.
2. Chinese-remainder conditions place those sets in separated blocks while preventing the forbidden divisibility relation across blocks.
3. The blocks are large enough that the union eventually exceeds every fixed N^(1-c) threshold.
Sources and attribution: Pinned Lean source (0647711a7118), Human-written proof companion for Erdős 12(ii), Erdős Problems 12 source record, Felix Behrend (1946), original PNAS paper, p. 331
standard axioms: Classical.choice, Quot.sound, propext what this means
Statement uses: Iff, False, Exists, Real, And, GT.gt, OfNat.ofNat, Set, Nat, Erdos12.IsGood, Set.Infinite, setOf, LT.lt, Set.ncard, Inter.inter, Set.Icc, HPow.hPow, HSub.hSub
Proof uses: Iff.rfl, Eq.mpr, id, Eq, congrArg, propext, Iff.intro, False.elim, Min.min, HDiv.hDiv, lt_min, lt_of_not_ge, LE.le, Mathlib.Tactic.Linarith.lt_irrefl, Eq.mp, HAdd.hAdd, Neg.neg, HMul.hMul, inferInstance, AddMonoidWithOne and 96 more
119 instances, coercions and auxiliary constants left out.

Distinct definitions of this name: APNOutputs/ErdosProblems/erdos_12.parts.i.lean:1228 (different declaration text). Qualify references as Erdos12.target_theorem_0@path.

Tactic trace: 32 steps
Open to load the checked before-and-after goal states.
```
theorem target_theorem_0
  : answer(False) ↔ ∃ c > (0 : ℝ), ∀ (A : Set ℕ), IsGood A → {N : ℕ | (A ∩ Icc 1 N).ncard < (N : ℝ) ^ (1 - c)}.Infinite := by
…
```
Mentions: Erdos12.IsGood