166 problems · 60 unsolved
Pick one.
Every statement is already formalized in Lean by formal-conjectures. Easy ones are warm-ups with known proofs. Unsolved ones are open research problems.
Unsolved60
PNPPNP · sorry — nobody on itConjectures in Complexity TheoryNSNS · sorry — nobody on itExistence And Smoothness Of The Navier–Stokes EquationRHRH · sorry — nobody on itRiemann Hypothesis and its generalizationsE101E101 · sorry — nobody on itErdős Problem 101E1020E1020 · sorry — nobody on itErdős Problem 1020E1029E1029 · sorry — nobody on itErdős Problem 1029E1030E1030 · sorry — nobody on itErdős Problem 1030E104E104 · sorry — nobody on itErdős Problem 104E1107E1107 · sorry — nobody on itErdős Problem 1107E1167E1167 · sorry — nobody on itErdős Problem 1167E159E159 · sorry — nobody on itErdős Problem 159E233E233 · sorry — nobody on itErdős Problem 233E236E236 · sorry — nobody on itErdős Problem 236E242E242 · sorry — nobody on itErdős Problem 242E243E243 · sorry — nobody on itErdős Problem 243E282E282 · sorry — nobody on itErdős Problem 282E364E364 · sorry — nobody on itErdős Problem 364E371E371 · sorry — nobody on itErdős Problem 371E373E373 · sorry — nobody on itErdős Problem 373E41E41 · sorry — nobody on itErdős Problem 41E535E535 · sorry — nobody on itErdős Problem 535E563E563 · sorry — nobody on itErdős Problem 563E572E572 · sorry — nobody on itErdős Problem 572E583E583 · sorry — nobody on itErdős Problem 583E617E617 · sorry — nobody on itErdős Problem 617E779E779 · sorry — nobody on itErdős Problem 779E82E82 · sorry — nobody on itErdős Problem 82E859E859 · sorry — nobody on itErdős Problem 859E89E89 · sorry — nobody on itErdős Problem 89E982E982 · sorry — nobody on itErdős Problem 982AgAg · sorry — nobody on itAgoh-Giuga conjectureBeBe · sorry — nobody on itBeck–Fiala theorem and conjectureBrBr · sorry — nobody on itBrocard's ConjectureBcBc · sorry — nobody on itBüchi's problemCaCa · sorry — nobody on itCarmichael's totient function conjectureCtCt · sorry — nobody on itCatalan's conjecture and related Diophantine equationsCoCo · sorry — nobody on itCongruent NumberAbAb · sorry — nobody on itConjectures about Mersenne primesDiDi · sorry — nobody on itDickson's conjectureEuEu · sorry — nobody on itEuler's sum of powers conjectureFeFe · sorry — nobody on itFeit-Thompson conjecture on primesGaGa · sorry — nobody on itGap conjectureGrGr · sorry — nobody on itGraceful Tree Conjecture (Ringel–Kotzig conjecture)HaHa · sorry — nobody on itHadamard's conjectureHlHl · sorry — nobody on itHall's conjectureInIn · sorry — nobody on itInfinitude of Wall–Sun–Sun primesJuJu · sorry — nobody on itJuggler conjectureKuKu · sorry — nobody on itKummer–Vandiver conjectureKtKt · sorry — nobody on itKöthe conjectureLaLa · sorry — nobody on itLander, Parkin, and Selfridge ConjectureLeLe · sorry — nobody on itLehmer's Mahler measure problemLoLo · sorry — nobody on itLocal uniformizationLnLn · sorry — nobody on itLonely runner conjectureMoMo · sorry — nobody on itMoving Sofa ProblemOpOp · sorry — nobody on itOpen questions regarding the existence of Euler bricksRH₂RH₂ · sorry — nobody on itParticular values of the Riemann zeta functionPiPi · sorry — nobody on itPierce–Birkhoff conjecturePoPo · sorry — nobody on itPollock's (tetrahedral numbers) conjectureLvLv · sorry — nobody on itThe Lovász–Plummer conjecture (proved 2011) and Sheehan's conjectureVaVa · sorry — nobody on itVaught conjecture
Hard30
NS₂NS₂ · known result, no worker yetExistence And Smoothness Of The Navier–Stokes EquationPoiPoi · known result, no worker yetPoincareE194E194 · known result, no worker yetErdős Problem 194E275E275 · known result, no worker yetErdős Problem 275E277E277 · known result, no worker yetErdős Problem 277E31E31 · known result, no worker yetErdős Problem 31E437E437 · known result, no worker yetErdős Problem 437E438E438 · known result, no worker yetErdős Problem 438E482E482 · known result, no worker yetErdős Problem 482E484E484 · known result, no worker yetErdős Problem 484E519E519 · known result, no worker yetErdős Problem 519E645E645 · known result, no worker yetErdős Problem 645E646E646 · known result, no worker yetErdős Problem 646E690E690 · known result, no worker yetErdős Problem 690E728E728 · known result, no worker yetErdős Problem 728AoAo · known result, no worker yetAgoh-Giuga conjectureBkBk · known result, no worker yetBeck–Fiala theorem and conjectureBoBo · known result, no worker yetBrocard's ConjectureCrCr · known result, no worker yetCarmichael's totient function conjectureElEl · known result, no worker yetEuler's sum of powers conjectureGoGo · known result, no worker yetGromov's theorem on groups of polynomial growthJaJa · known result, no worker yetJacobian conjectureJcJc · known result, no worker yetJacobson ConjectureLgLg · known result, no worker yetLegendre's conjectureLiLi · known result, no worker yetLeinster GroupsLcLc · known result, no worker yetLocal uniformizationPePe · known result, no worker yetPierce–Birkhoff conjectureSnSn · known result, no worker yetSnake in the boxLsLs · known result, no worker yetThe Lovász–Plummer conjecture (proved 2011) and Sheehan's conjectureErEr · known result, no worker yetČerný Conjecture
Medium38
CmCm · known result, no worker yetConjectures in Complexity TheoryE1049E1049 · known result, no worker yetErdős Problem 1049E1054E1054 · known result, no worker yetErdős Problem 1054E12E12 · known result, no worker yetErdős Problem 12E18E18 · known result, no worker yetErdős Problem 18E19E19 · known result, no worker yetErdős Problem 19E295E295 · known result, no worker yetErdős Problem 295E317E317 · known result, no worker yetErdős Problem 317E329E329 · known result, no worker yetErdős Problem 329: Maximum Density of Sidon SetsE358E358 · known result, no worker yetErdős Problem 358E42E42 · known result, no worker yetErdős Problem 42: Maximal Sidon Sets and Disjoint Difference SetsE44E44 · known result, no worker yetErdős Problem 44: Extending Sidon SetsE68E68 · known result, no worker yetErdős Problem 68E69E69 · known result, no worker yetErdős Problem 69E872E872 · known result, no worker yetErdős Problem 872DoDo · known result, no worker yetDoubling distributes over additionEvEv · known result, no worker yetEvery natural number is even or oddEeEe · known result, no worker yetEvery power of two is positiveGuGu · known result, no worker yetGauss's formula, doubledReRe · known result, no worker yetRemainders repeat with period sevenRvRv · known result, no worker yetReversing a list twice gives the list backGeGe · known result, no worker yetThe greatest common divisor of a number with itself is the numberMiMi · known result, no worker yetThe minimum never exceeds the maximumAhAh · known result, no worker yetAgoh-Giuga conjectureBaBa · known result, no worker yetBeal conjectureCiCi · known result, no worker yetCarmichael's totient function conjectureCnCn · known result, no worker yetCongruent NumberAuAu · known result, no worker yetConjectures about Mersenne primesCwCw · known result, no worker yetConway's 99-graph problemGtGt · known result, no worker yetGottschalk's surjunctivity conjectureIfIf · known result, no worker yetInfinitude of Pell number primesIiIi · known result, no worker yetInfinitude of Wall–Sun–Sun primesJoJo · known result, no worker yetJacobson ConjectureMvMv · known result, no worker yetMoving Sofa ProblemPlPl · known result, no worker yetPollock's (tetrahedral numbers) conjectureRsRs · known result, no worker yetResolution of singularitiesSoSo · known result, no worker yetSome conjectures about ranks of elliptic curves over ℚWoWo · known result, no worker yetWolstenholme Prime
Easy38
RH₃RH₃ · known result, no worker yetRiemann Hypothesis and its generalizationsE107E107 · known result, no worker yetErdős Problem 107E1074E1074 · known result, no worker yetErdős Problem 1074E156E156 · known result, no worker yetErdős Problem 156E282₂E282₂ · known result, no worker yetErdős Problem 282E287E287 · known result, no worker yetErdős Problem 287E36E36 · known result, no worker yetErdős Problem 36E361E361 · known result, no worker yetErdős Problem 361E366E366 · known result, no worker yetErdős Problem 366E445E445 · known result, no worker yetErdős Problem 445E448E448 · known result, no worker yetErdős Problem 448E602E602 · known result, no worker yetErdős Problem 602E80E80 · known result, no worker yetErdős Problem 80E90E90 · known result, no worker yetErdős Problem 90: The unit distance problemE937E937 · known result, no worker yetErdős Problem 937AdAd · known result, no worker yetAdding zero on the right changes nothingAiAi · known result, no worker yetAddition of natural numbers is commutativeEnEn · known result, no worker yetAn even number leaves remainder zeroEyEy · known result, no worker yetEvery number is less than its successorFiFi · known result, no worker yetThe first eleven numbers sum to fifty-fiveLtLt · known result, no worker yetThe length of a concatenation is the sum of the lengthsThTh · known result, no worker yetThree divides twelveTwTw · known result, no worker yetTwo plus two is fourAGAG · known result, no worker yetAgoh-Giuga conjectureBhBh · known result, no worker yetBüchi's problemCcCc · known result, no worker yetCarmichael's totient function conjectureClCl · known result, no worker yetCatalan's conjecture and related Diophantine equationsCgCg · known result, no worker yetCongruent NumberGcGc · known result, no worker yetGraceful Tree Conjecture (Ringel–Kotzig conjecture)GmGm · known result, no worker yetGromov's theorem on groups of polynomial growthHdHd · known result, no worker yetHadamard's conjectureHH · known result, no worker yetHall's conjectureJbJb · known result, no worker yetJacobian conjectureJgJg · known result, no worker yetJuggler conjectureLlLl · known result, no worker yetLocal uniformizationLyLy · known result, no worker yetLychrel numbers in base 10ScSc · known result, no worker yetScholz conjecture on addition chainsSaSa · known result, no worker yetSnake in the box
Open · sorry Known result Worker on it Proved here
60 shown
- Conjectures in Complexity Theorytheorem P_ne_NP : P ≠ NPunsolved
- Existence And Smoothness Of The Navier–Stokes Equationtheorem navier_stokes_existence_and_smoothness_R3 (nu : ℝ) (hnu : nu > 0) (u₀ : ℝ³ → ℝ³) (hu₀ : InitialVelocityConditionDecay u₀) : ∃ v p, NavierStokesExistenceAndSmoothnessRn nu u₀ (f := 0) v punsolved
- Riemann Hypothesis and its generalizationstheorem riemannHypothesis : RiemannHypothesisunsolved
- Erdős Problem 101theorem erdos_101 : (fun n => (numLinesWithFourPointMax n : ℝ)) =o[atTop] (fun n => (n : ℝ)^2)unsolved
- Erdős Problem 1020theorem erdos_1020 (r : ℕ) (hr : 3 ≤ r) (n k : ℕ) (hk : 0 < k) (hrk : r * k - 1 ≤ n) : f n r k = max ((r * k - 1).choose r) (n.choose r - (n - k + 1).choose r)unsolved
- Erdős Problem 1029theorem erdos_1029 : Tendsto (fun k : ℕ ↦ (SimpleGraph.diagonalRamsey k : ℝ) / ((k : ℝ) * (2 : ℝ) ^ ((k : ℝ) / 2))) atTop atTopunsolved
- Erdős Problem 1030theorem erdos_1030 : ∃ c > (0 : ℝ), ∃ L : ℝ, Tendsto (fun k : ℕ ↦ (SimpleGraph.classicalRamsey (k + 1) k : ℝ) / (SimpleGraph.classicalRamsey k k : ℝ)) atTop (nhds L) ∧ L > 1 + cunsolved
- Erdős Problem 104theorem erdos_104 : (fun n : ℕ => (maxUnitCircleCount n : ℝ)) =o[atTop] (fun n : ℕ => (n : ℝ) ^ 2)unsolved
- Erdős Problem 1107theorem erdos_1107 : ∀ r ≥ 2, ∀ᶠ n in atTop, SumOfRPowerful r nunsolved
- Erdős Problem 1167theorem finite_targets (r : ℕ) (hr : 2 ≤ r) (lam : Cardinal.{u}) (hlam : ℵ₀ ≤ lam) (γ : Ordinal.{u}) (hγ : 2 ≤ γ) (n : γ.ToType → ℕ) : cardinalPartitionRel ((2 : Cardinal.{u}) ^ lam) (r + 1) γ (fun α => (n α : Cardinal.{u}) + 1) → cardinalPartitionRel lam r γ (fun α => (n α : Cardinal.{u}))unsolved
- Erdős Problem 159theorem erdos_159 : ∃ (c : ℝ) (_ : 0 < c) (C : ℝ), ∀ (n : ℕ), 1 ≤ n → (SimpleGraph.graphRamsey (SimpleGraph.cycleGraph 4) (SimpleGraph.completeGraph (Fin n)) : ℝ) ≤ C * (n : ℝ) ^ (2 - c)unsolved
- Erdős Problem 233theorem erdos_233 : (fun N => ((∑ n ∈ Finset.range N, (primeGap n) ^ 2) : ℝ)) =O[atTop] fun N => N * (log N)^2unsolved
- Erdős Problem 236theorem erdos_236: (fun n => (f n : ℝ)) =o[atTop] (fun n => Real.log (n : ℝ))unsolved
- Erdős Problem 242theorem erdos_242 (n : ℕ) (hn : 2 < n) : ∃ x y z : ℕ, 1 ≤ x ∧ x < y ∧ y < z ∧ (4 / n : ℚ) = 1 / x + 1 / y + 1 / zunsolved
- Erdős Problem 243theorem erdos_243 (a : ℕ → ℕ) (ha₀ : StrictMono a) (ha₁ : Tendsto (fun n ↦ (a n : ℝ) / a (n - 1) ^ 2) atTop (𝓝 1)) (ha₂ : Summable ((1 : ℚ) / a ·)) : ∀ᶠ n in atTop, a n = a (n - 1) ^ 2 - a (n - 1) + 1unsolved
- Erdős Problem 282theorem erdos_282 {x : ℚ} (hx : x ∈ Set.Ioo 0 1) (hx_den : Odd x.den) : greedyUnitFractionRem { n | Odd n } x =ᶠ[atTop] 0unsolved
- Erdős Problem 364theorem erdos_364 : ¬ ∃ (n : ℕ), Powerful n ∧ Powerful (n + 1) ∧ Powerful (n + 2)unsolved
- Erdős Problem 371theorem erdos_371 : { n | Nat.maxPrimeFac (n + 1) > Nat.maxPrimeFac n }.HasDensity (1/2)unsolved
- Erdős Problem 373theorem erdos_373 : S.Finiteunsolved
- Erdős Problem 41theorem erdos_41 (A : Set ℕ) (h_triple : NtupleCondition A 3) (h_infinite : A.Infinite) : Filter.atTop.liminf (fun N => (A ∩ Icc 1 N).ncard / (N : ℝ)^(1/3 : ℝ)) = 0unsolved
- Erdős Problem 535theorem erdos_535 : ∀ r ≥ 3, ∃ c > (0 : ℝ), ∀ᶠ (N : ℕ) in atTop, (f r N : ℝ) ≤ (N : ℝ) ^ (c / log (log (N : ℝ)))unsolved
- Erdős Problem 563theorem erdos_563 : ∀ (α : ℝ), 0 ≤ α → α < 1 / 2 → ∃ (c : ℝ), 0 < c ∧ Tendsto (fun n : ℕ => (F n α : ℝ) / Real.log n) atTop (nhds c)unsolved
- Erdős Problem 572theorem erdos_572 (k : ℕ) (hk : 3 ≤ k) : ∃ c > (0 : ℝ), ∀ᶠ (n : ℕ) in atTop, c * (n : ℝ) ^ (1 + 1 / (k : ℝ)) ≤ (SimpleGraph.extremalNumber n (SimpleGraph.cycleGraph (2 * k)) : ℝ)unsolved
- Erdős Problem 583theorem erdos_583 {V : Type*} [Fintype V] (G : SimpleGraph V) (hG : G.Connected) : ∃ D : Finset G.Subgraph, (∀ H ∈ D, IsPathSubgraph H) ∧ IsDecomposition G D ∧ D.card ≤ ⌈(Fintype.card V : ℚ) / 2⌉₊unsolved
- Erdős Problem 617theorem erdos_617 (r : ℕ) (hr : r ≥ 3) {V : Type} [Fintype V] [DecidableEq V] (hV : Fintype.card V = r^2 + 1) (coloring : Sym2 V → Fin r) : ∃ (S : Finset V) (k : Fin r), S.card = r + 1 ∧ ∀ u ∈ S, ∀ v ∈ S, u ≠ v → coloring s(u, v) ≠ kunsolved
- Erdős Problem 779theorem erdos_779 (n : ℕ) (hn : n ≥ 1): let P := ∏ i ∈ range (n + 1), nth Nat.Prime i ∃ p, p.Prime ∧ (P + p).Prime ∧ nth Nat.Prime n < p ∧ p < Punsolved
- Erdős Problem 82theorem erdos_82 : Tendsto (fun n => F n / Real.log n) atTop atTopunsolved
- Erdős Problem 859theorem erdos_859 : ∃ c₁ > 0, ∃ c₂ > (0 : ℝ), ∃ d : ℕ → ℝ, (∀ t > 0, (DivisorSumSet t).HasDensity (d t)) ∧ (fun (t : ℕ) ↦ d t) ~[atTop] (fun t ↦ c₁ / Real.log t ^ c₂)unsolved
- Erdős Problem 89theorem erdos_89 : (fun (n : ℕ) => n/(n : ℝ).log.sqrt) =O[atTop] (fun n => (minimalDistinctDistances ℝ² n : ℝ))unsolved
- Erdős Problem 982theorem erdos_982 (n : ℕ) (hn : 3 ≤ n) (p : Fin n → ℝ²) (hp : Function.Injective p) (hp' : EuclideanGeometry.IsConvexPolygon p) : ∃ (i : Fin n), { d : ℝ | ∃ j : Fin n, j ≠ i ∧ d = dist (p i) (p j) }.ncard ≥ n / 2unsolved
- Agoh-Giuga conjecturetheorem agoh_giuga : AgohGiugaCongrunsolved
- Beck–Fiala theorem and conjecturetheorem beck_fiala_conjecture : ∃ C : ℝ, 0 < C ∧ ∀ (n m t : ℕ) (S : Fin m → Finset (Fin n)), (∀ j, (Finset.univ.filter fun i => j ∈ S i).card ≤ t) → ∃ χ : Fin n → ℝ, (∀ j, χ j = 1 ∨ χ j = -1) ∧ ∀ i, |∑ j ∈ S i, χ j| ≤ C * Real.sqrt tunsolved
- Brocard's Conjecturetheorem brocard_conjecture (n : ℕ) (hn : 1 ≤ n) : letI prev := n.nth Nat.Prime; letI next := (n+1).nth Nat.Prime; 4 ≤ ((Ioo (prev^2) (next^2)).filter Nat.Prime).cardunsolved
- Büchi's problemtheorem buchi_problem_M5 : IsBuchi 5unsolved
- Carmichael's totient function conjecturetheorem charmichaelTotient : ∀ ⦃n : ℕ⦄, 0 < n → CarmichaelTotientFor nunsolved
- Catalan's conjecture and related Diophantine equationstheorem pillais_conjecture (a b c : ℕ) (ha : 0 < a) (hb : 0 < b) (hc : 0 < c) : { (x, y, m, n) : (ℕ × ℕ × ℕ × ℕ) | 1 < x ∧ 1 < y ∧ 1 < m ∧ 1 < n ∧ (m, n) ≠ (2, 2) ∧ a * x^n - b * y^m = c }.Finiteunsolved
- Congruent Numbertheorem Tunnell_odd_converse (n : ℕ) (hsqf : Squarefree n) (hodd : Odd n) : 2 * (A n).ncard = (B n).ncard → congruentNumber nunsolved
- Conjectures about Mersenne primestheorem new_mersenne_conjecture (p : ℕ) (hp : Odd p) : NewMersenneConjectureStatement punsolved
- Dickson's conjecturetheorem dickson_conjecture (fs : Finset ℤ[X]) (hfs : ∀ f ∈ fs, f.degree = 1 ∧ BunyakovskyCondition f) (hfs' : SchinzelCondition fs) : Infinite {n : ℕ | ∀ f ∈ fs, (f.eval (n : ℤ)).natAbs.Prime}unsolved
- Euler's sum of powers conjecturetheorem eulers_sum_of_powers_conjecture (n k b : ℕ) (hn : 1 < n) (hk : 5 < k) (a : Fin n → ℕ) (ha : ∀ i, a i > 0) (hsum : ∑ i, (a i) ^ k = b ^ k) : k ≤ nunsolved
- Feit-Thompson conjecture on primestheorem feit_thompson_primes (p q : ℕ) (hp : p.Prime) (hq : q.Prime) (h : p < q) : ¬ (q ^ p - 1) / (q - 1) ∣ (p ^ q - 1) / (p - 1)unsolved
- Gap conjecturetheorem gap_conjecture : ∀ (G : Type) [Group G] (S : Set G), S.Finite → Subgroup.closure S = ⊤ → HasSuperPolynomialGrowth G → ∃ C : ℕ, 0 < C ∧ ∀ᶠ n : ℕ in atTop, Real.exp (Real.sqrt (n : ℝ)) ≤ (GrowthFunction S (C * n) : ℝ)unsolved
- Graceful Tree Conjecture (Ringel–Kotzig conjecture)theorem graceful_tree_conjecture {V : Type*} [Fintype V] [DecidableEq V] (T : SimpleGraph V) [DecidableRel T.Adj] (hT : T.IsTree) : let m := T.edgeFinset.card ∃ f : V → ℕ, Function.Injective f ∧ (∀ v, f v ≤ m) ∧ T.edgeFinset.image (fun e => e.lift ⟨fun u v => Int.natAbs ((f u : ℤ) - (f v : ℤ)), fun u v => by show ((f u : ℤ) - f v).natAbs = ((f v : ℤ) - f u).natAbs rw [← Int.natAbs_neg, neg_sub]⟩) = Finset.Icc 1 munsolved
- Hadamard's conjecturetheorem HadamardConjecture (k : ℕ) : ∃ M, IsHadamard (n := 4 * k) Munsolved
- Hall's conjecturetheorem hall_conjecture : HallConjectureExp 2⁻¹unsolved
- Infinitude of Wall–Sun–Sun primestheorem exists_isWallSunSunPrime : ∃ p, IsWallSunSunPrime punsolved
- Juggler conjecturetheorem juggler_conjecture (n : ℕ) (hn : n > 0) : ∃ m, jugglerStep^[m] n = 1unsolved
- Kummer–Vandiver conjecturetheorem kummer_vandiver (p : ℕ+) (hp : p.Prime) : ¬ ↑p ∣ (classNumber (maximalRealSubfield (CyclotomicField p ℚ)))unsolved
- Köthe conjecturetheorem KotheConjecture (I J : Ideal R) (hI : IsNil I) (hJ : IsNil J) : IsNil (I + J)unsolved
- Lander, Parkin, and Selfridge Conjecturetheorem lander_parkin_selfridge : ∀ (k n m : ℕ) (x : Fin n → ℕ) (y : Fin m → ℕ), 0 < n → 0 < m → (∀ i, 0 < x i) → (∀ j, 0 < y j) → (∀ i j, x i ≠ y j) → ∑ i, x i ^ k = ∑ j, y j ^ k → k ≤ n + munsolved
- Lehmer's Mahler measure problemtheorem lehmer_mahler_measure_problem : ∃ μ : ℝ, ∀ f : ℤ[X], μ > 1 ∧ (mahlerMeasureZ f > 1 → mahlerMeasureZ f ≥ μ)unsolved
- Local uniformizationtheorem local_uniformization (k F : Type*) [Field k] [Field F] [Algebra k F] [Algebra.EssFiniteType k F] (p : ℕ) [Fact p.Prime] [CharP k p] (𝒪 : ValuationSubring F) (hk : ∀ x : k, algebraMap k F x ∈ 𝒪) : 𝒪.HasLocalUniformization kunsolved
- Lonely runner conjecturetheorem lonely_runner_conjecture (n : ℕ) (speed : Fin n ↪ ℝ) (lonely : Fin n → ℝ → Prop) (lonely_def : ∀ r t, lonely r t ↔ ∀ r2 : Fin n, r2 ≠ r → dist (t * speed r : UnitAddCircle) (t * speed r2) ≥ 1 / n) (r : Fin n) : ∃ t ≥ 0, lonely r tunsolved
- Moving Sofa Problemtheorem volume_eq_sofaConstant_iff_congruent_gerversSofa (s : Set ℝ²) (hs : ∃ m, IsMovingSofa s m) : volume s = sofaConstant ↔ ∃ g : E(2), s = g '' gerversSofaunsolved
- Open questions regarding the existence of Euler brickstheorem n_dim_euler_brick_existence :unsolved
- Particular values of the Riemann zeta functiontheorem irrational_seven : ∃ x, Irrational x ∧ riemannZeta 7 = xunsolved
- Pierce–Birkhoff conjecturetheorem pierce_birkhoff_conjecture {n : ℕ} (f : (Fin n → ℝ) → ℝ) (hf : IsPiecewiseMvPolynomial f) : ∃ (ι κ : Type) (g : ι → κ → MvPolynomial (Fin n) ℝ), Finite ι ∧ Finite κ ∧ ∀ x, f x = ⨆ i, ⨅ j, MvPolynomial.eval x (g i j)unsolved
- Pollock's (tetrahedral numbers) conjecturetheorem pollock_tetrahedral (N : ℕ) : ∃ f : Fin 5 → ℕ, N = ∑ i, tetrahedral (f i)unsolved
- The Lovász–Plummer conjecture (proved 2011) and Sheehan's conjecturetheorem sheehan_conjecture : ∀ {V : Type} [Fintype V] [DecidableEq V] (G : SimpleGraph V) [DecidableRel G.Adj], (∀ v, G.degree v = 4) → ∀ (v : V) (c : G.Walk v v), IsHamiltonianCycle G c → ∃ (w : V) (c' : G.Walk w w), IsHamiltonianCycle G c' ∧ c'.edges.toFinset ≠ c.edges.toFinsetunsolved
- Vaught conjecturetheorem vaught_conjecture {L : FirstOrder.Language} (hL : Countable L.Symbols) {T : L.Theory} (hT : T.IsComplete) : numberOfCountableModels T ≤ Cardinal.aleph0 ∨ numberOfCountableModels T = Cardinal.continuumunsolved