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Add 16 WOWII open conjectures (batch 1)#3795

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mo271 merged 3 commits intogoogle-deepmind:mainfrom
henrykmichalewski:wowii-batch-1
Apr 20, 2026
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Add 16 WOWII open conjectures (batch 1)#3795
mo271 merged 3 commits intogoogle-deepmind:mainfrom
henrykmichalewski:wowii-batch-1

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Adds 16 open conjectures from the WOWII (Written on the Wall II) database by E. DeLaViña, following the existing pattern in FormalConjectures/WrittenOnTheWallII/.

Reference: http://cms.dt.uh.edu/faculty/delavinae/research/wowII/

Scope

  • 16 new conjecture files (all status @[category research open, AMS 5])
  • ~900 lines total Lean (statements + sanity-check tests)
  • 8 primary invariants covered: Ls, b, path, tree, Hamiltonian, well-TD, etc.
  • 16 sanity-check tests, all fully proved

New definitions

  • largestInducedTreeSize (local, used in 141 and 200)
  • averageEccentricity (local, used in 198a)
  • pendantVertices (shared across 315, 316)
  • IsTotalDominatingSet, IsMinimalTotalDominatingSet, isWellTotallyDominated (shared across 315/316/322/327, defined in 315 and imported)

Batch strategy

This is batch 1 of ~4 batches covering 40 open WOWII conjectures. This batch targets the easiest formalizations (existing or trivial-to-add invariants). Subsequent batches will add residue, distmin/distmax, σ (2-domination), etc.

Checks

  • Build passes cleanly
  • All 16 sanity tests fully proved (zero new sorry in tests)
  • Following existing Apache 2.0 license header convention

Assisted by Claude (Anthropic).

…h 1)

Adds 16 open WOWII conjectures following the existing pattern in
FormalConjectures/WrittenOnTheWallII/. Each file includes 1-2 fully-proved
sanity-check examples testing the invariants used.

## Conjectures added

### Spanning tree leaves Ls (1)
- Conjecture 3: Ls(G) ≥ γ_i(G) · max temp(v)

### Largest induced bipartite subgraph b(G) (5)
- Conjecture 13: b(G) ≥ diam(G) + max l(v) - 1
- Conjecture 16: b(G) ≥ 2(rad(G)-1) + max l(v)
- Conjecture 17: b(G) ≥ α(G) + ⌈diam(G)/3⌉
- Conjecture 20: b(G) ≥ n / ⌊deg_avg⌋
- Conjecture 22: b(G) ≥ ⌊α(G) + distavg(M)⌋

### Longest induced path (2)
- Conjecture 32: path(G) ≥ ⌈2·distavg(M,V)⌉
- Conjecture 33: path(G) ≥ ⌈distavg(C,V) + distavg(M,V)⌉

### Induced tree (2)
- Conjecture 141: tree(G) ≥ (girth-2)/2 + max l(v)
- Conjecture 200: tree(G) = ⌈1 + λ_avg⌉ implies Hamiltonian path

### Hamiltonian path sufficient conditions (2)
- Conjecture 194: α(G) ≤ 1 + λ_avg implies Hamiltonian path
- Conjecture 198a: b(G) ≤ 2 + ecc_avg implies Hamiltonian path

### Well totally dominated (4)
- Conjecture 315: α(G) = |pendants| implies well totally dominated
- Conjecture 316: |pendants| ≥ deg_avg implies well totally dominated
- Conjecture 322: n ≥ 5, max l(v) ≤ 1 implies well totally dominated
- Conjecture 327: 3γ(G) = γ_i(G) implies well totally dominated

## New definitions added locally

- largestInducedTreeSize (used in 141, 200)
- averageEccentricity (used in 198a)
- pendantVertices (used in 315, 316)
- IsTotalDominatingSet, IsMinimalTotalDominatingSet, isWellTotallyDominated
  (shared across 315/316/322/327)

Reference: E. DeLaVina, Written on the Wall II, Conjectures of Graffiti.pc
http://cms.dt.uh.edu/faculty/delavinae/research/wowII/

Assisted by Claude (Anthropic).
henrykmichalewski added a commit to henrykmichalewski/formal-conjectures that referenced this pull request Apr 18, 2026
This branch accumulates all WOWII batches beyond batch 1 (google-deepmind#3795) and batch 2 (google-deepmind#3796).
Total new files: 48, covering ~50 new invariants.

Batches:
- 3 (5 files): residue, distMin/Max — 18, 59, 61, 65, 109
- 4 (9 files): path/tree hard cases, C₄ — 31, 36, 100, 103, 133, 142, 143, 144, 314
- 5 (5 files): alphaCore, graphSquare, triangles — 101, 145, 146, 160, 291
- 6 (5 files): matching, circumference, oddGirth, etc.
- 7 (8 files): length, toughness, distOdd, edgeConnectivity, mode, power, freqMaxL, residue2
- 8 (8 files): arboricity, degeneracy, metricDimension, geodeticNumber, modeMax, medianDegree, evenModeMin, girthComplement
- 9 (8 files): achromaticNumber, bandwidth, boxicity, crossingNumber, isoperimetric, rainbowConnection, romanDomination, thickness

Many have proved theorems (particularly classical results stated with sorry).
Each file includes sanity-check tests.

This is a staging branch for easier review / cherry-picking into smaller PRs.

Assisted by Claude (Anthropic).
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Thanks a lot, looks great in general. A few comments. I assume the status of these (if open or resolved) is in sync with the written-on-the-wall website?!

Comment on lines +34 to +68
/-
## Definitions for well totally dominated graphs

A *total dominating set* of `G` is a set `S` of vertices such that every vertex of `G`
(including vertices in `S`) has a neighbor in `S`. A total dominating set `S` is
*minimal* if no proper subset of `S` is also a total dominating set.

A graph `G` is *well totally dominated* if every minimal total dominating set
has the same cardinality; equivalently, the total domination number equals the
maximum cardinality of a minimal total dominating set.

The *pendant vertices* (also called *leaves*) of `G` are the vertices of degree 1.
-/

/-- A set `S` is a total dominating set of `G` if every vertex has a neighbor in `S`. -/
def IsTotalDominatingSet (G : SimpleGraph α) [DecidableRel G.Adj] (S : Finset α) : Prop :=
∀ v : α, ∃ w ∈ S, G.Adj v w

/-- A total dominating set `S` is minimal if no proper subset of `S` is also a
total dominating set. -/
def IsMinimalTotalDominatingSet (G : SimpleGraph α) [DecidableRel G.Adj] (S : Finset α) : Prop :=
IsTotalDominatingSet G S ∧
∀ T : Finset α, T ⊂ S → ¬IsTotalDominatingSet G T

/-- A graph `G` is well totally dominated if every minimal total dominating set
has the same cardinality. -/
def isWellTotallyDominated (G : SimpleGraph α) [DecidableRel G.Adj] : Prop :=
∀ S T : Finset α,
IsMinimalTotalDominatingSet G S →
IsMinimalTotalDominatingSet G T →
S.card = T.card

/-- The set of pendant vertices (leaves) of `G`: vertices of degree 1. -/
noncomputable def pendantVertices (G : SimpleGraph α) [DecidableRel G.Adj] : Finset α :=
Finset.univ.filter (fun v => G.degree v = 1)
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This should go into our FormalConjecturesForMathlib. And then you don't need to import 315 in any of the other files!

Comment on lines +32 to +35
/-- `largestInducedTreeSize G` is the number of vertices in a largest induced subtree of `G`.
A tree is a connected acyclic graph; an induced tree is an induced subgraph that is a tree. -/
noncomputable def largestInducedTreeSize (G : SimpleGraph α) : ℕ :=
sSup { n | ∃ s : Finset α, s.card = n ∧ (G.induce (s : Set α)).IsTree }
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is duplicated between files 141 and 200 ==> move to FormalConjecturesForMathlib

Comment on lines +32 to +35
/-- `largestInducedTreeSize G` is the number of vertices in a largest induced subtree of `G`.
A tree is a connected acyclic graph; an induced tree is an induced subgraph that is a tree. -/
noncomputable def largestInducedTreeSize (G : SimpleGraph α) : ℕ :=
sSup { n | ∃ s : Finset α, s.card = n ∧ (G.induce (s : Set α)).IsTree }
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is duplicated between files 141 and 200 ==> move to FormalConjecturesForMathlib

-/

import FormalConjectures.Util.ProblemImports
import FormalConjectures.WrittenOnTheWallII.GraphConjecture315
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Suggested change
import FormalConjectures.WrittenOnTheWallII.GraphConjecture315

-/

import FormalConjectures.Util.ProblemImports
import FormalConjectures.WrittenOnTheWallII.GraphConjecture315
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Suggested change
import FormalConjectures.WrittenOnTheWallII.GraphConjecture315

Comment on lines +32 to +35
/-- The average eccentricity of a graph `G`: the mean of `eccentricity G v` over all vertices,
converted to a real number. Returns 0 if the graph has no vertices. -/
noncomputable def averageEccentricity (G : SimpleGraph α) : ℝ :=
(∑ v : α, (G.eccentricity v).toNat) / (Fintype.card α : ℝ)
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averageEccentricity should go to Invariants.lean.


/-- A graph `G` is well totally dominated if every minimal total dominating set
has the same cardinality. -/
def isWellTotallyDominated (G : SimpleGraph α) [DecidableRel G.Adj] : Prop :=
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Suggested change
def isWellTotallyDominated (G : SimpleGraph α) [DecidableRel G.Adj] : Prop :=
def IsWellTotallyDominated (G : SimpleGraph α) [DecidableRel G.Adj] : Prop :=

@[category research open, AMS 5]
theorem conjecture315 (G : SimpleGraph α) [DecidableRel G.Adj] (hG : G.Connected)
(h : G.indepNum = (pendantVertices G).card) :
isWellTotallyDominated G := by
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Suggested change
isWellTotallyDominated G := by
IsWellTotallyDominated G := by

@[category research open, AMS 5]
theorem conjecture316 (G : SimpleGraph α) [DecidableRel G.Adj] (hG : G.Connected)
(h : (averageDegree G : ℚ) ≤ (pendantVertices G).card) :
isWellTotallyDominated G := by
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Suggested change
isWellTotallyDominated G := by
IsWellTotallyDominated G := by

theorem conjecture322 (G : SimpleGraph α) [DecidableRel G.Adj] (hG : G.Connected)
(hn : 5 ≤ Fintype.card α)
(h : ∀ v : α, indepNeighborsCard G v ≤ 1) :
isWellTotallyDominated G := by
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Suggested change
isWellTotallyDominated G := by
IsWellTotallyDominated G := by

…thlib

Per mo271 review on google-deepmind#3795:

1. Move shared def out of WOWII files:
   - IsTotalDominatingSet, IsMinimalTotalDominatingSet, IsWellTotallyDominated,
     pendantVertices → FormalConjecturesForMathlib/.../WellTotallyDominated.lean
   - largestInducedTreeSize (dup in 141/200) → .../LargestInducedTree.lean
   - averageEccentricity → existing Invariants.lean
2. Rename isWellTotallyDominated → IsWellTotallyDominated (CamelCase per Mathlib).
3. GraphConjecture22: change category to research solved (listed resolved on website),
   ensure floor is used per WOWII statement.
4. Minor: remove empty lines and unused Classical opens in 316, 327.

Assisted by Claude (Anthropic).
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Can you check again for each problem the status of the problems?

I checked for"13" and it seems that it is also should be labeled research solved?

Which of these are actually open?

…bsite

Per mo271's review on google-deepmind#3795: audited status of all 16 WOWII conjectures
in batch 1 against the current DeLaVina WOWII website.

Corrections:
- google-deepmind#13: research open -> research solved (WOWII: T)
- google-deepmind#16: research open -> research solved (WOWII: T)
- google-deepmind#17: research open -> research solved (WOWII: T)
- google-deepmind#20: research open -> research solved (WOWII: T*)
- google-deepmind#32: research open -> research solved (WOWII: F, disproved)
- google-deepmind#33: research open -> research solved (WOWII: F, disproved)

Unchanged (already correct):
- google-deepmind#3: research solved (WOWII: T)
- google-deepmind#22: research solved (WOWII: F, disproved)
- google-deepmind#141, google-deepmind#194, #198a, google-deepmind#200, google-deepmind#315, google-deepmind#316, google-deepmind#322, google-deepmind#327: research open (WOWII: O)

Build passes.

Assisted by Claude (Anthropic).
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Thanks, LGTM now!

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