Vela Mathematics Program: problems

Problem ledger

576 problems · 7/12Number SourcesGraph view

declared proved (Lean) · formalizederdos:484

∃ c, 0 < c ∧ ∀ (k : ℕ), 0 < k → ∃ N₀, ∀ (N : ℕ), N₀ ≤ N → ∀ (f : ℕ → Fin k), c * ↑N ≤ ↑{n ∈ Finset.Icc 1 N | ∃ a ∈ Finset.Icc 1 N, ∃ b ∈ Finset.Icc 1 N, a ≠ b ∧ f a = f b ∧ a + b = n}.card

number theoryadditive combinatoricsramsey theoryN/A5 sources

declared open · formalizederdos:486

True ↔ ∀ (X : (n : ℕ) → Set (ZMod n)), ∃ d, {m | ∀ (n : ℕ), ↑m ∉ X n}.HasLogDensity d

number theoryprimitive setsN/A2 sources

declared proved (Lean) · formalizederdos:487

True ↔ ∀ (A : Set ℕ), A.HasPosDensity → ∃ a ∈ A, ∃ b ∈ A, ∃ c ∈ A, a ≠ b ∧ b ≠ c ∧ a ≠ c ∧ a.lcm b = c

number theoryN/A5 sources

declared falsifiable · formalizederdos:488

True ↔ ∀ (A : Finset ℕ), A.Nonempty → 0 ∉ A → 1 ∉ A → ∀ (n m : ℕ), m > n → A.max ≤ ↑n → ↑{x ∈ Finset.Icc 1 m | x ∈ {n | n ≥ 1 ∧ ∃ a ∈ A, a ∣ n}}.card / ↑m < 2 * ↑{x ∈ Finset.Icc 1 n | x ∈ {n | n ≥ 1 ∧ ∃ a ∈ A, a ∣ n}}.card / ↑n

number theoryN/A3 sources

declared open · formalizederdos:489

A

is a forbidden-divisor set with

|A \cap [1,x]| = o(\sqrt{x})

and

B = \{b_1 < b_2 < \cdots\}

the sifted set, must

x^{-1} \sum_{b_i < x} (b_{i+1} - b_i)^2

converge to a finite limit?

number theoryN/A4 sources

declared proved (Lean)erdos:490

Erdős problem 490

number theoryA3972054 sources

declared provederdos:491

Erdős problem 491

number theoryN/A

declared disprovederdos:492

Erdős problem 492

number theoryN/A

declared proved (Lean) · formalizederdos:493

True ↔ ∃ k N, ∀ (n : ℤ), N ≤ n → ∃ a, (∀ (i : Fin k), 2 ≤ a i) ∧ ∏ i, a i - ∑ i, a i = n

number theoryN/A5 sources

declared open · formalizederdos:495

True ↔ ∀ (α β : ℝ), Filter.liminf (fun n => ↑n * distToNearestInt (↑n * α) * distToNearestInt (↑n * β)) Filter.atTop = 0

diophantine approximationnumber theoryN/A2 sources

declared provederdos:496

Erdős problem 496

number theorydiophantine approximationN/A

declared open · formalizederdos:520

True ↔ ∃ c > 0, ∀ (Ω : Type) [inst : MeasureTheory.MeasureSpace Ω] [MeasureTheory.IsProbabilityMeasure MeasureTheory.volume] (f : ℕ → Ω → ℝ), Erdos520.IsRademacherMultiplicative f → ∀ᵐ (ω : Ω), Filter.limsup (fun N => ∑ m ∈ Finset.Iic N, f m ω / √(↑N * Real.log (Real.log ↑N))) Filter.atTop = c

number theoryprobabilityN/A2 sources

declared openerdos:530

Erdős problem 530

number theorysidon setsA143824 · possible

declared openerdos:531

Erdős problem 531

number theoryramsey theorypossible

declared proved (Lean) · formalizederdos:532

True ↔ ∀ (c : ℕ → Fin 2), ∃ A, A.Infinite ∧ ∃ color, ∀ (S : Finset ℕ), S.Nonempty → ↑S ⊆ A → c (∑ n ∈ S, n) = color

number theoryramsey theoryN/A4 sources

declared solvederdos:534

Erdős problem 534

number theoryintersecting familyA387543 · A387698

declared open · formalizederdos:535

∀ r ≥ 3, ∃ c > 0, ∀ᶠ (N : ℕ) in Filter.atTop, ↑(Erdos535.f r N) ≤ ↑N ^ (c / Real.log (Real.log ↑N))

number theorypossible3 sources

declared open · formalizederdos:536

True ↔ ∀ ε > 0, ∀ᶠ (N : ℕ) in Filter.atTop, ∀ A ⊆ Finset.Icc 1 N, ε * ↑N ≤ ↑A.card → ∃ a ∈ A, ∃ b ∈ A, ∃ c ∈ A, {a, b, c}.card = 3 ∧ a.lcm b = b.lcm c ∧ b.lcm c = a.lcm c

number theorypossible3 sources

declared disproved (Lean) · formalizederdos:537

False ↔ ∀ (ε : ℝ), 0 < ε → ∀ᶠ (N : ℕ) in Filter.atTop, ∀ A ⊆ Finset.Icc 1 N, ↑A.card ≥ ε * ↑N → ∃ a₁ ∈ A, ∃ a₂ ∈ A, ∃ a₃ ∈ A, ∃ p₁ p₂ p₃, Nat.Prime p₁ ∧ Nat.Prime p₂ ∧ Nat.Prime p₃ ∧ p₁ ≠ p₂ ∧ p₁ ≠ p₃ ∧ p₂ ≠ p₃ ∧ a₁ * p₁ = a₂ * p₂ ∧ a₂ * p₂ = a₃ * p₃

number theorypossible5 sources

declared open · formalizederdos:538

If each integer has at most

r

representations

m = pa

with

p

prime and

a \in A \subseteq [1, N]

, what is the best upper bound for

\sum_{a \in A} 1/a

? The candidate proof gives the matching order

\Theta_r(\log N / \log\log N)

number theoryN/A5 sources

declared open · formalizederdos:539

For

|A| = n

, how small can the cofactor set

Q(A) = \{a / \gcd(a,b) : a, b \in A\}

be? The answer is

h(n) = n^{1/2 + o(1)}

: a new upper bound

h(n) \le n^{1/2} \exp(O(\sqrt{\log n}))

matches the classical lower bound.

number theorypossible5 sources

declared proved (Lean) · formalizederdos:540

True ↔ ∃ C, 0 < C ∧ ∀ (N : ℕ), 0 < N → ∀ (A : Finset (ZMod N)), C * √↑N ≤ ↑A.card → Erdos540.HasZeroSubsetSum A

number theoryA0344635 sources

declared proved (Lean) · formalizederdos:541

True ↔ ∀ (p : ℕ), Fact (Nat.Prime p) → ∀ (a : Fin p → ZMod p), (∃ r, ∀ (S : Finset (Fin p)), S ≠ ∅ → ∑ i ∈ S, a i = 0 → S.card = r) → (Set.range a).ncard ≤ 2

number theoryN/A5 sources

declared solvederdos:542

Erdős problem 542

number theoryN/A

declared disprovederdos:543

Erdős problem 543

number theorygroup theorypossible3 sources

declared disprovederdos:586

Erdős problem 586

number theorycovering systemsN/A

declared solved · formalizederdos:587

∃ O > 0, ∃ O' > 0, ∀ᶠ (N : ℕ) in Filter.atTop, ↑(Erdos587.MaxNotSqSum N) ≤ O' * Real.nthRoot 3 ↑N * Real.log ↑N ^ O

number theoryA3720402 sources

declared openerdos:635

Erdős problem 635

number theoryN/A2 sources

declared proved (Lean) · formalizederdos:645

∀ (c : ℕ → Bool), ∃ x d, 0 < x ∧ x < d ∧ ∃ C, c x = C ∧ c (x + d) = C ∧ c (x + 2 * d) = C

number theoryadditive combinatoricsramsey theoryN/A5 sources

declared proved (Lean) · formalizederdos:646

True ↔ ∀ (S : Finset ℕ), (∀ p ∈ S, Nat.Prime p) → {n | ∀ p ∈ S, Even (padicValNat p n.factorial)}.Infinite

number theoryfactorialsN/A5 sources

declared verifiable · formalized · £25erdos:647

sorry ↔ ∃ n > 24, ⨆ m, ↑m + (ArithmeticFunction.sigma 0) ↑m ≤ n + 2

number theoryA062249 · A0872804 sources

declared solved (Lean) · formalizederdos:648

(fun n => ↑(Erdos648.g n)) =Θ[Filter.atTop] fun n => √(↑n / Real.log ↑n)

number theoryA3917505 sources

declared disproved (Lean) · formalizederdos:649

False ↔ ∀ (p q : ℕ), Nat.Prime p → Nat.Prime q → ∃ n, n.maxPrimeFac = p ∧ (n + 1).maxPrimeFac = q

number theorypossible5 sources

declared solved (Lean) · formalizederdos:650

∀ (m : ℕ), Erdos650.f m = min m ⌈2 * √↑m⌉₊

number theoryA0274346 sources

declared provederdos:656

Erdős problem 656

number theoryadditive combinatoricsN/A

declared openerdos:663

Erdős problem 663

number theoryA391668

declared verifiable · formalizederdos:672

True ↔ ∀ (k l : ℕ), l > 1 → k ≥ 4 → Erdos672.Erdos672With k l

number theoryN/A2 sources

declared provederdos:673

Erdős problem 673

number theorydivisorsN/A

declared proved (Lean) · formalizederdos:674

True ↔ Erdos674.solutionSet.Nonempty

number theoryN/A4 sources

declared openerdos:675

Erdős problem 675

number theoryN/A2 sources

declared openerdos:676

Erdős problem 676

number theoryA390181 · in progress

declared open · formalizederdos:677

∀ (m n k : ℕ), k > 0 → m ≥ n + k → Finset.lcmInterval m k ≠ Finset.lcmInterval n k

number theorypossible2 sources

declared proved (Lean) · formalizederdos:678

True ↔ ∀ᶠ (k : ℕ) in Filter.atTop, {(m, n) | n + k ≤ m ∧ Finset.lcmInterval m (k + 1) < Finset.lcmInterval n k}.Nonempty

number theorypossible5 sources

declared openerdos:679

Erdős problem 679

number theoryN/A2 sources

declared open · formalizederdos:680

True ↔ ∀ᶠ (n : ℕ) in Filter.atTop, ∃ k, k ≠ 0 ∧ (n + k).minFac > k ^ 2 + 1

number theoryprimesN/A2 sources

declared open · formalizederdos:681

True ↔ ∀ᶠ (n : ℕ) in Filter.atTop, ∃ k > 0, (n + k).Composite ∧ ∀ (p : ℕ), Erdos681.IsLPF p (n + k) → p > k ^ 2

number theoryprimesA3896802 sources

declared provederdos:682

Erdős problem 682

number theoryprimesA386978

declared open · formalizederdos:683

True ↔ ∃ c > 0, ∀ (n k : ℕ), 0 < k ∧ k < n → ↑(Erdos683.P n k) > min (↑n - ↑k + 1) (↑k ^ (1 + c))

number theoryprimesbinomial coefficientsA006530 · A074399 · A121359 · possible2 sources

declared openerdos:684

For the least

k

at which the small-prime part of

\binom{n}{k}

exceeds

n^2

, how large can

f(n)

be?

number theoryprimesbinomial coefficientsA392019 · possible3 sources

declared openerdos:685

Erdős problem 685

number theoryprimesbinomial coefficientsN/A

Problems · Vela Mathematics Program

Problem ledger

Search problems.science