Reconstruction conjecture

Outstanding ★★★★ Graph Theory

Status partial high confidence

The Reconstruction Conjecture remains open for general graphs. Since the problem was posted in 2007, notable partial progress includes: computational verification for all graphs up to 13 vertices (McKay 2021), improved reconstruction-from-smaller-decks results for trees (Groenland–Johnston–Scott–Tan 2021), and a proof that every interval graph on at least 3 vertices is reconstructible (Heinrich–Kiyomi–Otachi–Schweitzer 2025). No counterexample or general proof has been established.

Cited literature (4)

  • Brendan D. McKay · arXiv preprint · arXiv:2102.01942

    Computationally verifies the graph reconstruction conjecture for all graphs up to 13 vertices (and tournaments up to 13, digraphs up to 9), extending the previously established verification bound.

  • Carla Groenland, Tom Johnston, Alex Scott, Jane Tan · arXiv preprint · arXiv:2103.13359

    Shows trees can be reconstructed from their $(n-r)$-deck for $r \le n/9 + o(n)$, and proves connectivity and degree-sequence can be recovered from much smaller partial decks.

  • Irene Heinrich, Masashi Kiyomi, Yota Otachi, Pascal Schweitzer · arXiv preprint · arXiv:2504.02353

    Proves that every interval graph on at least 3 vertices is reconstructible (and reconstructible in polynomial time), resolving a longstanding open case via new structural techniques for graph separations.

  • Emilie Dufresne, Gabriela Jeronimo, Jenny Kenkel, Haydee Lindo, Nelly Villamizar · arXiv preprint · arXiv:2604.16567

    Surveys the reconstruction conjecture and develops an invariant-theoretic algebraic reformulation, aiming to show that polynomials distinguishing decks also distinguish the original graphs.

Reviewer notes. A 2023 paper in Information Sciences (ScienceDirect pii/S0020025523014433) titled 'Vertex-substitution framework verifies the reconstruction conjecture for finite undirected graphs' claims a general proof, but could not be accessed (HTTP 403) and Wikipedia does not list it as a resolution — likely a flawed or unaccepted claimed proof. The arXiv:2501.19081 paper (Kim–Lee 2025) concerns matching polynomial reconstruction for hypergraphs and is not directly about the graph reconstruction conjecture. McKay's paper was submitted in 2021 with a final arXiv revision in January 2022; journal venue not confirmed from available pages. Groenland et al. 2103.13359 was last revised November 2023, possibly in press.

Auto-reviewed 2026-05-08 with claude-sonnet-4-6 (worker 05) (web search enabled).

Conjecture. If two graphs on $ \ge 3 $ vertices have the same deck, then they are isomorphic.
Keywords: reconstruction

Discussion

See Wikipedia's Reconstruction Conjecture for more on this problem.

Bibliography

  • [K] P. J. Kelly, A congruence theorem for trees, Pacific J. Math., 7 (1957), 961–968.
  • [U] S. M. Ulam, A collection of mathematical problems, Wiley, New York, 1960.