Finite geometry and incidence structures

Prime-power conjecture for finite projective planes

Collaboration beta

Must every finite projective plane have prime-power order? The packet reports substantial incidence, code, and lattice structure, but no route presently turns that structure into a proof for all orders.

n=pe
Known results and sources
A deterministic card diagram of a seven-point projective plane beside the open question asking whether every finite-plane order is a prime power.
A representative prime-power plane frames the universal order question; the diagram does not depict a proof.

Research problem

Exact mathematical statement

Let Π=(P,L)\Pi=(\mathcal P,\mathcal L) be a finite projective plane of order n2n\ge 2. Prove that there are a prime pp and an integer e1e\ge 1 such that

n=pe.n=p^e.

This is the exact order conjecture reported by the governing source. The source explicitly says that no full proof is claimed.

Problem infographic

Problem at a glance

A deterministic argument map separates the finite-plane axioms and prime-power question from the packet-reported square-core results, the LK-4 barrier, and three open routes.
Source-reported structure narrows the research frontier but does not close the prime-power conjecture.

Current mathematical picture

Where work on Prime-power conjecture for finite projective planes stands

Open conjecture

Selected route highlights from the mathematical source. This is not yet a complete mathematical inventory.

Useful failureProper equal-weight subset cancellation

The source reports LK-4 as proving that no such proper subset can provide the needed divisibility. Cross-direction rank growth, strict higher-p-adic support, and simultaneous two-frame geometry remain source-reported open programs.

Route status · Narrowed route
Main reductionCurrent reduction

The current work organizes the remaining work around three non-equivalent open interfaces: target-character rank increments, incompatibility of two distinguished root frames, and strict target-supported higher-p-adic filtrations.

Evidence posture · Source-reported route statement · dependencies incomplete
Priority open bridgeFor a prime p sharply dividing n, prove the required target-character rank-increment inequality with the exact endpoint and equality hypotheses.Task status · Ready to work on

Work mapped so far

Prime-power conjecture for finite projective planes in numbers

1.1kretained lines of mathematical investigation1,060 in the current working snapshot
Argument development
887 · 84%
Explored or eliminated routes
42 · 4%
Computational analysis
14 · 1%
Open obligations
35 · 3%
Definitions and setup
82 · 8%
7selected mapped statements1routes investigated5open questions5contribution-ready tasks
How this is measured

This measures retained mathematical investigation, not proximity to a proof. Code, data, logs, repeated text, operational instructions, and generated presentation copy are excluded.

Argument map and routes

How the current approaches connect

Claims, reductions, open questions, active routes, and narrowed alternatives in one mathematical map.

Visible working map

Research route map

13 selected steps

Selected claims, active routes, useful failures, and open questions from the current research map. Arrows appear only for explicitly recorded relationships.

13 selected steps

Scroll horizontally to explore the route

Working route overview for Prime-power conjecture for finite projective planesA selected map of recorded claims, active routes, useful failures, open questions, and their explicit relationships. Search, filter, zoom, or pan within this page.FINITE PROJECTIVE PLANE OF ORDER n -> IS n A PRIME POWER? — Depends on missing premiseFINITE PROJECTIVE PLANE OFORDER n -> IS n A PRIMEPOWER?Current reduction — Depends on missing premiseCurrent reductionClosed subset-cancellation route — Depends on missing premiseClosed subset-cancellationrouteClosing target — Depends on missing premiseClosing targetEndpoint cokernel split — Depends on missing premiseEndpoint cokernel splitRootless unitary factor lattices — Depends on missing premiseRootless unitary factorlatticesSquare-core similarity — Depends on missing premiseSquare-core similarityProper equal-weight subset cancellation — stoppedProper equal-weight subsetcancellationFor a prime p sharply dividing n, prove the required target-character rank-increment inequality with the exact endpoint and equality hypotheses. — OpenFor a prime p sharplydividing n, prove therequired…For a nontrivial coprime factorization n = ab, prove an obstruction to the two distinguished finite-index root frames inside the even rootless factor lattice. — OpenFor a nontrivial coprimefactorization n = ab, provean…For repeated prime powers, construct the strict target-supported character module and control its difference from the global-filtration intersection. — OpenFor repeated prime powers,construct the stricttarget-supported…Exact order question — OpenExact order questionThree live research branches — OpenThree live research branches
Working claimActive routeOpen, active, or blocked questionUseful failure

Working overview, not proof. The map shows selected recorded relationships; more nodes or edges do not establish correctness or completion.

Explored alternatives

Other routes

1 recorded
Narrowed routeProper equal-weight subset cancellation

The source reports LK-4 as proving that no such proper subset can provide the needed divisibility. Cross-direction rank growth, strict higher-p-adic support, and simultaneous two-frame geometry remain source-reported open programs.

Route status · Narrowed route

More ways to contribute

Open questions

Additional prepared tasks for exploring this research frontier.

5 featured tasks
01
For a prime p sharply dividing n, prove the required target-character rank-increment inequality with the exact endpoint and equality hypotheses.Suggested move: Start with MC-A when 2 sharply divides n: formulate the class-addition rank map on target blocks and test the one-chain bound without promoting MC-1 from conjectural status.
Ready to work on
02
For a nontrivial coprime factorization n = ab, prove an obstruction to the two distinguished finite-index root frames inside the even rootless factor lattice.Suggested move: Analyze the minimum shell and vector-valued theta constraints in the TF-B and TF-C cases, retaining all coprimality and rootlessness hypotheses.
Ready to work on
03
Exact order question

The source asks whether the order n of every finite projective plane is p^e for some prime p and e at least one.

Suggested move: Resolve the exact source-reported obligation without treating it as an established negative result.
Ready to work on
04
Three live research branches

The source prioritizes target-character rank increments, two-frame factor-lattice incompatibility, and strict higher-p-adic character filtrations as open branches.

Suggested move: Resolve the exact source-reported obligation without treating it as an established negative result.
Ready to work on
05
For repeated prime powers, construct the strict target-supported character module and control its difference from the global-filtration intersection.Suggested move: Carry out HPA-A for the smallest repeated-exponent example and define the correction quotient before asserting any subnet elementary-divisor formula.
Ready to work on

Sourced mathematical context

The known mathematical landscape

Context collected Aug 29, 2026
Current statusOpen conjecture

The conjecture remains open: finite projective planes exist for every prime-power order, but no plane of non-prime-power order is known. Order 12 is the smallest order whose existence remains unknown; current order-12 results impose strong symmetry restrictions without resolving existence.

[6][5]
External progress

What the literature has established

Selected external milestones in reverse chronological order, with their evidence posture.

  1. Peer reviewedAkiyama, Suetake, and Tanaka ruled out an order-12 plane with a collineation group of order 4 and, with earlier exclusions, concluded that any collineation group of a hypothetical order-12 plane has order 1, 2, or 3.[5]
  2. Computational resultLam, Thiel, and Swiercz combined their exhaustive search with earlier results to rule out a projective plane of order 10, the first excluded order satisfying the Bruck-Ryser necessary condition.[2]
  3. Historical sourceBruck and Ryser recorded the prime-power-order question as unsettled and proved an arithmetic nonexistence obstruction for orders congruent to 1 or 2 modulo 4.[1]
6 cited sources2 related results or reductionsReferences

Mathematical neighborhood

Related results and reusable starting points

Current focusPrime Power Conjecture for Finite Projective Planes
Related problemExistence of a finite projective plane of order 12

Order 12 is the smallest unresolved order. An order-12 plane would have 157 points and 157 lines, with 13 points on every line, but existing symmetry exclusions do not settle its existence.

[6][5]
Dependency or reductionBruck-Ryser nonexistence obstruction

The Bruck-Ryser arithmetic condition excludes many candidate non-prime-power orders but is silent for orders congruent to 0 or 3 modulo 4, including order 12.

[1]

Formalization opportunities

Lean work can make these reusable foundations precise without being presented as a proof of the core problem.

  • Formalization targetAn end-to-end formal proof or counterexample for the unrestricted prime-power-order assertion.
  • Formalization targetMachine-checkable bridges from any retained arithmetic or computational exclusions to their exact finite-projective-plane statements.

Detailed research inventory

Claims, milestones, and routes in the current map

This view highlights the mathematical statements most useful for following the current route.

5 standing statements2 proposed statements5 open questions1 narrowed routes
Statements by mathematical role7 selected mapped statements
  • theorem candidate1 of 71
  • reduction1 of 71
  • lemma4 of 74
  • negative result1 of 71
Selected mathematical clusters1 mathematical clusters
Current research mapThe conjecture, retained reductions, explored limitations, and open questions represented in this overview.20 displayed rows · 1 route included
  • retained route statementFINITE PROJECTIVE PLANE OF ORDER n -> IS n A PRIME POWER?
  • retained route statementCurrent reductionintermediate
  • retained route statementClosing targetintermediate
  • retained route statementSquare-core similarityintermediate
  • retained route statementEndpoint cokernel splitintermediate
  • retained route statementRootless unitary factor latticesintermediate
  • retained route statementClosed subset-cancellation routeintermediate
  • Recorded relationshipThe source reports this as a route toward the conjecture; missing or unaudited premises remain and the reduction does not itself prove the target.supports · reported by source
  • Recorded relationshipThis source-reported claim supports the retained route only within its stated, unaudited scope.supports · reported by source
  • Recorded relationshipThis source-reported claim supports the retained route only within its stated, unaudited scope.supports · reported by source
  • Recorded relationshipThis source-reported claim supports the retained route only within its stated, unaudited scope.supports · reported by source
  • Recorded relationshipThis source-reported claim supports the retained route only within its stated, unaudited scope.supports · reported by source
  • DerivationThe source reports that completing the closing target would advance the reduction to the main conjecture; this remains an informal route, not a verified derivation.proposed
  • Useful failureProper equal-weight subset cancellationreported failure
  • Research targetFor a prime p sharply dividing n, prove the required target-character rank-increment inequality with the exact endpoint and equality hypotheses.open
  • Research targetFor a nontrivial coprime factorization n = ab, prove an obstruction to the two distinguished finite-index root frames inside the even rootless factor lattice.open
  • Research targetFor repeated prime powers, construct the strict target-supported character module and control its difference from the global-filtration intersection.open
  • Research targetExact order questionopen
  • Research targetThree live research branchesopen
  • Narrowed routeProper equal-weight subset cancellationThe source reports LK-4 as proving that no such proper subset can provide the needed divisibility. Cross-direction rank growth, strict higher-p-adic support, and simultaneous two-frame geometry remain source-reported open programs.
How to interpret these counts

A statement may be a lemma, conditional reduction, special case, documented limitation, or open target. These counts describe the work's structure; they do not estimate distance to a proof.

Research outlook

Conditions that would advance the current route

Priority open bridgeFor a prime p sharply dividing n, prove the required target-character rank-increment inequality with the exact endpoint and equality hypotheses.

1 approach has already been tested and narrowed. The task above is the current priority within the larger open route.

Evidence needed nextConcrete conditions for progress

A result can change the outlook by closing the bridge, narrowing its scope, or showing that the route cannot work.

  • Supply a complete argument with every imported premise identified.
  • Survive an independent attempt to falsify the proposed step.

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Prepared starting pointFor a prime p sharply dividing n, prove the required target-character rank-increment inequality with the exact endpoint and equality hypotheses.

Prime-power conjecture for finite projective planes · ready to start

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Research contextPrepared context for any AI agent

Must every finite projective plane have prime-power order? The current work reports substantial incidence, code, and lattice structure, but no route presently turns that structure into a proof for all orders.

  • Exact question and boundaries
  • Current routes and known obstacles
  • What a useful result should report
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Sources and references6 cited works · next context review by Nov 29, 2026

The mathematical context was checked on Aug 29, 2026. Status can be refreshed sooner after a material result or claim.

  1. 1
    The Nonexistence of Certain Finite Projective Planesoriginal source · R. H. Bruck, H. J. Ryser · Canadian Journal of Mathematics · 1949-02-01 · DOI 10.4153/CJM-1949-009-2 · accessed Aug 29, 2026
  2. 2
    The Non-Existence of Finite Projective Planes of Order 10peer reviewed result · C. W. H. Lam, L. Thiel, S. Swiercz · Canadian Journal of Mathematics · 1989 · DOI 10.4153/CJM-1989-049-4 · accessed Aug 29, 2026
  3. 3
    Another case of the prime power conjecture for finite projective planespeer reviewed result · Dieter Jungnickel, Marialuisa J. de Resmini · Advances in Geometry · 2002 · accessed Aug 29, 2026
  4. 4
    Doubly transitive sets of even permutationspeer reviewed result · Gábor P. Nagy · Bulletin of the Academy of Sciences of the Republic of Moldova, Mathematics · 2016 · accessed Aug 29, 2026
  5. 5
    Projective planes of order 12 do not have a collineation group of order 4peer reviewed result · Kenzi Akiyama, Chihiro Suetake, Masaki Tanaka · Journal of Combinatorial Designs · 2023 · DOI 10.1002/jcd.21869 · accessed Aug 29, 2026
  6. 6
    Forbidden Sidon subsets of perfect difference sets, featuring a human-assisted proofpreprint · Boris Alexeev, Dustin G. Mixon · arXiv · 2026-01-16 (v2) · ARXIV 2510.19804 · accessed Aug 29, 2026

Important qualifications

  • This scoped collection prioritizes original and peer-reviewed papers plus one recent primary preprint; it is not an exhaustive bibliography of finite projective planes.
  • The freshest explicit general-status source is the January 2026 revision of a preprint. A scoped search through 2026-08-29 found no later accepted resolution, but absence from that search is not proof of nonexistence.
  • The exact proposer and proposal year remain unknown. Bruck and Ryser described the question as already unsettled in 1949, while Nagy later described the commonly grouped Prime Power Conjecture assertions as folklore.
  • This record covers only the assertion that the order of every finite projective plane is a prime power. It excludes the separate prime-order Desarguesianity conjecture and the restricted cyclic-plane variants.
  • This collection did not establish an end-to-end formalization of the unrestricted conjecture or independently reproduce the cited computational exclusions.

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