Open problems from the 1980s

Results on questions first raised the 1980s, going by the earliest step each entry records.

60 AI-made results on questions first raised the 1980s, from 128 papers in the OpenAI math collection, each explained in plain English. 34 have a formal Lean proof listed; 26 are claimed in a paper and not yet machine-checked. They span 16 fields, led by differential geometry (10), algebraic and complex geometry (5) and partial differential equations (5). The oldest question here dates back to 1980: The exact Sobolev endpoint for Schrödinger convergence. Results rated Landmark include Log abundance for compact Kähler spaces under logarithmic Iitaka subadditivity and The Falconer distance conjecture.

Number theory4

  • 001Oct 7, 2026 Explained

    Milne’s rationality conjecture and algebraic specialization

    Proves Milne's rationality conjecture for abelian varieties over Q‾\overline{\mathbb Q} with good reduction: specialized Hodge classes pair rationally with complementary divisor products, independently of cohomology theory. Together with result 032, every specialized Hodge class is represented by a single rational algebraic cycle simultaneously in all prime-to-p and crystalline realizations, for every residue characteristic p.

    Claimed, not checked
  • 015Sep 24, 2026 Explained

    Torus-packet equidistribution in prime, quartic, and sextic degrees

    Proves Haar equidistribution without escape of mass for complete volume-weighted torus packets from totally real fields: arbitrary lattices and prescribed local types in fixed prime degree at least five, arbitrary-order Picard packets in primitive quartic fields, and maximal-order ideal-class packets in primitive sextic fields. Here primitive means having no proper intermediate field; the relevant order or field discriminant tends to infinity.

  • 019Sep 24, 2026 Explained

    The local p-adic section conjecture and global consequences

    Proves that rational points on every smooth proper geometrically connected curve of genus at least two over a finite extension of ℚp correspond bijectively to conjugacy classes of sections of its full arithmetic étale fundamental group. It also proves Grothendieck's section conjecture over ℚ for the modular curves X0(N)X_0(N) and X1(N)X_1(N) of genus at least two.

    Claimed, not checked
  • 031Oct 5, 2026 Explained

    Uchida’s conjecture for open homomorphisms of Galois groups

    Proves Uchida's conjecture: every continuous open homomorphism between Galois groups of possibly infinite solvably closed Galois extensions of number fields comes from a unique equivariant field embedding in the opposite direction. No restriction on the kernel or separate cyclotomic-compatibility assumption is needed.

    Claimed, not checked

Algebraic and complex geometry5

  • 034Sep 24, 2026 Explained

    Log abundance for compact Kähler spaces under logarithmic Iitaka subadditivity

    Using logarithmic Iitaka subadditivity, proves log abundance in every dimension for normal compact Kähler log canonical pairs with effective rational boundary: an analytically nef ℚ-Cartier adjoint is semiample. It also proves projective log abundance over every algebraically closed field of characteristic zero and the effective Iitaka fibration conjecture for smooth projective varieties of nonnegative Kodaira dimension in that setting. A further result resolves the finite-rational-coefficient index conjecture for connected projective semi-log-canonical log Calabi–Yau pairs over such fields in each fixed dimension and for each fixed finite set of rational boundary coefficients, with a uniform index independent of the number of components.

    Claimed, not checked
  • 035Sep 24, 2026 Explained

    Log-canonical threefold abundance in numerical dimension one

    Proves log abundance for projective log canonical threefold pairs over algebraically closed fields of characteristic p > 3 when the effective boundary is rational and the ℚ-Cartier adjoint is nef of numerical dimension one. The adjoint is semiample, without requiring the original variety to be terminal or ℚ-factorial.

    Claimed, not checked
  • 038Sep 23, 2026 Explained

    Fujita’s freeness conjecture

    Proves Fujita's freeness conjecture at its sharp bound in every dimension: for a smooth projective complex variety X of dimension n and an ample line bundle L, the adjoint KX+mLK_X+mL is globally generated for every integer m≥n+1m\ge n+1.

    Claimed, not checked
  • 056Sep 24, 2026 Explained

    Termination of projective and Kähler fourfold minimal model programs

    Proves termination of every existing generalized log canonical flip sequence on globally Weil ℚ-factorial compact Kähler fourfolds, with rational boundary, fixed rational analytically nef b-data, and projective small flip diagrams with the prescribed ample signs. Also proves termination of arbitrary permitted minimal model programs for projective log canonical fourfolds with rational boundary in characteristic zero.

    Claimed, not checked
  • 063Sep 24, 2026 Explained

    The generalized Mukai conjecture

    Proves the generalized Mukai conjecture: every positive-dimensional smooth complex projective Fano manifold of dimension n, Picard number ρ and pseudoindex ι satisfies ρ(ι−1)≤n\rho(\iota-1)\le n, with equality exactly for (Pι−1)ρ(\mathbb P^{\iota-1})^\rho. Here the pseudoindex is the least anticanonical degree of a rational curve.

    Claimed, not checked

Real and complex analysis2

  • 073Sep 23, 2026 Explained

    The Falconer distance conjecture

    Resolves the Falconer distance conjecture in every dimension d ≥ 2: every compact set E⊂RdE\subset\mathbb R^d with Hausdorff dimension greater than d/2d/2 determines a set of Euclidean distances of positive Lebesgue measure.

  • 080Sep 24, 2026 Explained

    The exact Sobolev endpoint for Schrödinger convergence

    Proves almost-everywhere convergence eitΔf→fe^{it\Delta}f\to f as t↓0t\downarrow0 for every f∈Hn/(2(n+1))(Rn)f\in H^{n/(2(n+1))}(\mathbb R^n) and every dimension n ≥ 2. This attains the sharp Sobolev equality case of Carleson's Schrödinger convergence problem, including the planar endpoint H1/3.

    Claimed, not checked

Convex and metric geometry3

  • 094Sep 23, 2026 Explained

    Subpolynomial dimension reduction in Lp

    For every fixed 1<p<∞1\lt p\lt \infty and distortion D > 1, every n-point subset of real Lp embeds into ℓpd\ell_p^d with distortion at most D and dimension d=no(1)d=n^{o(1)}, answering Naor's sublinear-dimension question for p ≠ 2. In contrast, exact embeddings require worst-case dimension Θ(n2)\Theta(n^2) when p ≠ 2.

  • 097Sep 24, 2026 Explained

    The Euclidean Steinitz–Bergström bound

    Proves that any finite sequence in the Euclidean unit ball of ℝd admits signs keeping every partial sum within CdC\sqrt d, independently of length. Consequently every zero-sum family can be reordered with the same bound on unsigned partial sums. A matching lower bound gives the optimal order S2(d)=Θ(d)S_2(d)=\Theta(\sqrt d).

  • 101Oct 5, 2026 Explained

    The sharp simplex conjecture for isotropic constants

    Proves that simplices uniquely maximize the isotropic constant among convex bodies in every dimension, resolving the strong isotropic constant conjecture. Also establishes the sharp entropy lower bound for log-concave probability densities, with equality precisely for invertible affine images of products of one-sided exponential laws.

    Claimed, not checked

Theoretical computer science4

Dynamical systems and ergodic theory2

Combinatorics3

  • 160Sep 23, 2026 Explained

    Superexponential van der Waerden numbers

    Resolves Erdős's superexponential-growth question for van der Waerden numbers. If Wr(k)W_r(k) is the least interval length forcing a monochromatic k-term progression in every r-coloring, then Wr(k)>kck⌊log⁡2r⌋W_r(k)\gt k^{ck\lfloor\log_2 r\rfloor} for an absolute c > 0, all r ≥ 2 and sufficiently large k, uniformly in r. In particular, Wr(k)1/k→∞W_r(k)^{1/k}\to\infty for each fixed r.

  • 178Sep 23, 2026 Explained

    Deterministic nonbipartite Ramanujan graphs in every fixed degree

    For every fixed d ≥ 3, constructs a simple d-regular nonbipartite Ramanujan graph on every sufficiently large even number n of vertices, with every nonconstant adjacency eigenvalue strictly between −2d−1-2\sqrt{d-1} and 2d−12\sqrt{d-1}. A deterministic algorithm outputs the full adjacency list in polynomial bit time, with exponent depending on d.

    Claimed, not checked
  • 184Sep 25, 2026 Explained

    Correspondence coloring with a fixed forbidden subgraph

    Proves the Alon–Krivelevich–Sudakov coloring conjecture in correspondence-coloring form: graphs avoiding any fixed subgraph F need OF(Δ/log⁡Δ)O_F(\Delta/\log\Delta) colors when their maximum degree Δ is sufficiently large. Also proves the Ajtai–Erdős–Komlós–Szemerédi independence conjecture: for fixed r ≥ 4, every n-vertex Kr-free graph of average degree d ≥ 2 has an independent set of size Ωr(nlog⁡d/d)\Omega_r(n\log d/d).

Algebra3

Probability and statistical mechanics4

  • 220Sep 23, 2026 Explained

    Directional zero–one laws beyond iid environments and iid ballisticity

    On ℤd, d ≥ 3, directional escape has probability zero or one for iid strictly elliptic nearest-neighbor environments, and for stationary ergodic finite-range-dependent environments under uniform ellipticity. In iid uniformly elliptic environments with d ≥ 2, almost-sure directional transience implies a deterministic limiting velocity with positive projection in that direction, resolving the ballisticity conjecture.

  • 222Sep 24, 2026 Explained

    Perceptron free energies and microscopic jamming exponents

    Determines finite-temperature variational free energies for Gaussian Ising perceptrons with bounded Borel log-potentials and Gaussian spherical perceptrons with bounded continuous potentials, at every positive pattern density. A spherical extension treats bi-orthogonally invariant disorder with compact limiting singular-value distributions and no outliers. At margin −1, the quadratic-penalty spherical model has a sharp feasibility threshold and limiting gap and force laws, with system size, zero temperature, and critical density taken in that order.

  • 225Sep 23, 2026 Explained

    Gaussian free field limits throughout the balanced six-vertex regime

    The balanced square-lattice six-vertex height field with a=b=1a=b=1 and 0<c≤20\lt c\le2 converges to a Gaussian free field, including at the endpoint c = 2. The plane state is defined by balanced-torus limits. For unit height increments and Green kernel −(2π)−1log⁡∣x−y∣-(2\pi)^{-1}\log|x-y|, the exact variance multiplier is 1/arcsin⁡(c/2)1/\arcsin(c/2).

    Claimed, not checked
  • 237Sep 26, 2026 Explained

    The three-quarter exponent for honeycomb self-avoiding walk

    Proves the diameter form of Nienhuis's predicted three-quarter exponent: a uniformly chosen n-step self-avoiding walk on the honeycomb lattice has diameter n3/4+o(1)n^{3/4+o(1)}. Its local mass and covering numbers have exponent 4/3. These estimates hold at every sufficiently large fixed length, simultaneously across scales, with arbitrarily high polynomial probability.

Group theory3

Mathematical physics4

  • 263Sep 24, 2026 Explained

    The ionization and generalized ionization conjectures

    For the full nonrelativistic Coulomb model with two electron spin states, proves that a molecule with M fixed nuclei of charges at least one and total charge Z strictly binds at most Z+CMZ+CM electrons. Neutral-atom first ionization energies and radii containing all but an expected half-electron have universal positive upper and lower bounds. The energy cost of removing m electrons has Thomas–Fermi asymptotics as m→∞m\to\infty and Z/m→∞Z/m\to\infty; neutral-atom outer radii have the corresponding iterated-limit asymptotics, taking Z→∞Z\to\infty first.

  • 268Sep 24, 2026 Explained

    The spin-one Haldane gap

    Proves the spin-one Haldane gap conjecture for the pure antiferromagnetic Heisenberg chain on even periodic rings: the spectral gap stays uniformly positive as the chain grows. A companion establishes a gap for odd open chains with endpoint field h=3/5h=3/5 and gives boundary-selected infinite-volume states with topological index −1.

    Claimed, not checked
  • 269Sep 24, 2026 Explained

    Uniform Laughlin gap and stability under bounded scalar disorder

    Proves the fermionic Laughlin spectral-gap conjecture for the full V1 interaction at filling 1/3 on the round sphere. The unique ground state remains uniformly gapped under sufficiently weak bounded real scalar one-body potentials projected to the lowest Landau level. Both the gap and disorder threshold are uniform over all sufficiently large particle numbers and all normalized potential profiles.

  • 282Sep 26, 2026 Explained

    From scale symmetry to local conformal symmetry in four-dimensional QFT

    Under the stated bounded-local-net and field-reconstruction hypotheses, proves that scale symmetry implies local conformal symmetry for four-dimensional unitary positive-energy theories with a discrete bounded-below scaling spectrum of finite multiplicity, finite scaling support and a physical local scale current. The stress tensor has a traceless improvement with unchanged spacetime charges. The conclusion concerns local Ward identities, not a global conformal action on the whole net.

    Claimed, not checked

Operator algebras3

  • 285Sep 23, 2026 Explained

    Counterexamples to Baum–Connes and Kadison–Kaplansky

    Disproves the coefficient-free reduced Baum–Connes conjecture through a failure of rational injectivity and a separate failure of surjectivity of assembly. A finitely generated torsion-free example witnesses the injectivity failure. Separately, a torsion-free group has a nontrivial projection in its reduced group C∗-algebra, disproving the Kadison–Kaplansky conjecture.

    Claimed, not checked
  • 286Sep 23, 2026 Explained

    Rigidity and arithmetic of lattice von Neumann algebras

    Classifies finite-index bimodules between scalar-twisted group factors of ICC groups commensurable with property-(T)(T) lattices over characteristic-zero local fields and arbitrary ICC group factors. Every such bimodule is a summand of finite sums of models arising from finite-index subgroup isomorphisms and finite-dimensional projective representations. The classification also recovers the group, scalar cocycle and amplification scale up to the stated stable equivalence.

    Claimed, not checked
  • 290Sep 23, 2026 Explained

    Relative bicentralizers and modular spectral recovery

    Proves Connes' bicentralizer conjecture for every type III1 factor with separable predual and every faithful normal state. More generally, for every inclusion N⊂MN\subset M of von Neumann algebras with separable preduals admitting a faithful normal conditional expectation, constructs an amenable expected subalgebra P⊂NP\subset N with P′∩c(M)=N′∩c(M)P'\cap c(M)=N'\cap c(M), resolving the relative bicentralizer conjecture.

Topology3

Functional analysis2

Differential geometry10

  • 335Sep 23, 2026 Explained

    Gromov’s integral scalar-curvature bound for simplicial volume

    Proves ∫M(Scalg−)n/2 dVg≥an∥M∥\int_M(\mathrm{Scal}_g^-)^{n/2}\,dV_g\ge a_n\lVert M\rVert for every closed connected oriented smooth n-manifold, n ≥ 3, and every smooth metric, with an>0a_n\gt 0 depending only on dimension. Here Scalg−=max⁡{0,−Scalg}\mathrm{Scal}_g^-=\max\{0,-\mathrm{Scal}_g\} and ∥M∥\lVert M\rVert is real simplicial volume. Also proves rational inessentiality under positive scalar curvature, resolving the Gromov–Lawson conjecture; every nonnegative-scalar-curvature metric on a closed aspherical manifold is flat.

    Claimed, not checked
  • 336Sep 23, 2026 Explained

    Spectral scalar curvature, Urysohn width, and macroscopic dimension

    Every complete connected smooth boundaryless n-manifold, n ≥ 3, satisfying −4Δ+Scal≥1-4\Delta+\mathrm{Scal}\ge1 as a quadratic-form inequality admits a continuous map to a simplicial complex of dimension at most n−2n-2 whose entire fibers have diameter bounded only by n in the original metric. This strengthens Gromov's width conclusion to spectral scalar curvature. Universal covers of closed positive-scalar-curvature manifolds also have continuous macroscopic dimension at most n−2n-2 for every n ≥ 2.

    Claimed, not checked
  • 338Sep 23, 2026 Explained

    Yau's uniformization conjecture

    Proves Yau's uniformization conjecture: every complete connected noncompact Kähler manifold with strictly positive holomorphic bisectional curvature is biholomorphic to ℂn.

    Claimed, not checked
  • 339Sep 23, 2026 Explained

    Katok's entropy rigidity conjecture

    Proves Katok's entropy rigidity conjecture for closed connected Riemannian manifolds of dimension at least three with strictly negative sectional curvature: normalized Liouville measure maximizes entropy for the geodesic flow if and only if the metric is locally symmetric.

    Claimed, not checked
  • 340Sep 23, 2026 Explained

    A counterexample to the nearby Lagrangian conjecture

    Disproves the unrestricted nearby Lagrangian conjecture. For some sufficiently large even N, constructs a closed exact embedded Lagrangian in T∗(S9×SN−1)T^*(S^9\times S^{N-1}) that is diffeomorphic to the base but not Hamiltonian isotopic to its zero section.

    Claimed, not checked
  • 343Sep 23, 2026 Explained

    Symplectic ball packing in higher dimensions

    Resolves the Siegel–Yao conjecture for arbitrary capacities in every dimension 2n≥62n\ge6. Finitely many closed symplectic balls of capacities R1,…,RkR_1,\ldots,R_k embed disjointly into an open ball of capacity R exactly when ∑iRin<Rn\sum_iR_i^n\lt R^n and Ri+Rj<RR_i+R_j\lt R for every distinct pair i, j.

  • 347Sep 23, 2026 Explained

    Counterexamples to stable-Morse and strong Arnold fixed-point bounds

    Disproves stable-Morse lower bounds for nondegenerate Hamiltonian fixed points: on simply connected closed Kähler manifolds of real dimension 22, the deficit below the stable Morse number is unbounded. A separate Hamiltonian diffeomorphism of the complex quadric threefold has exactly three fixed points, fewer than the four critical points required of every smooth function.

  • 350Sep 23, 2026 Explained

    Yau’s nodal bounds: surfaces and higher dimensions

    Proves the sharp CλC\sqrt\lambda upper bound for nodal length on every fixed smooth closed surface, completing Yau's conjecture there. The upper bound fails for fixed smooth metrics in dimensions three and four, including metrics on S3 arbitrarily close to round. In dimension five, nodal measure can grow faster than λ1/2+ε0\lambda^{1/2+\varepsilon_0} for some fixed ε0>0\varepsilon_0\gt 0, ruling out even arbitrarily small power losses.

  • 352Sep 24, 2026 Explained

    A finite-time singularity of Calabi flow

    Disproves Chen's smooth long-time existence conjecture for Calabi flow by constructing a smooth U(10)U(10)-invariant Kähler metric on CP10\mathbb{CP}^{10} whose flow develops a finite-time singularity. The metric lies in the Fubini–Study class, so the failure occurs even in a class containing a constant-scalar-curvature metric.

    Claimed, not checked
  • 361Sep 25, 2026 Explained

    Failure of integer-degree harmonic dimension comparison

    Disproves Yau's proposed Euclidean dimension bound for harmonic functions of integer growth on manifolds with nonnegative Ricci curvature. For every sufficiently large integer k, a complete smooth metric on ℝ3 has at least (k+2)2(k+2)^2 independent harmonic functions of growth at most k, exceeding the Euclidean count (k+1)2(k+1)^2. The metric may depend on k.

Partial differential equations5

Related