Vela Mathematics Program: problems

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576 problems · 2/12Number SourcesGraph view

declared open · formalized · $500erdos:66

True ↔ ∃ A c, c ≠ 0 ∧ Filter.Tendsto (fun n => ↑(AdditiveCombinatorics.sumRep A n) / Real.log ↑n) Filter.atTop (nhds c)

number theoryadditive basisN/A2 sources

declared open · formalizederdos:68

True ↔ Irrational (∑' (n : ℕ), 1 / (↑(n + 2).factorial - 1))

number theoryirrationalityA3313732 sources

declared proved · formalizederdos:69

Irrational (∑' (n : ℕ), ↑(ArithmeticFunction.cardDistinctFactors (n + 2)) / 2 ^ (n + 2))

number theoryirrationalityA2621532 sources

declared disprovederdos:121

Erdős problem 121

number theorysquaresA028391 · A013928 · A372306 · A373319 · A372306 · A373178 · A360659 · A373114 · A143301

declared openerdos:122

Erdős problem 122

number theoryN/A

declared proved (Lean) · formalized · $250erdos:123

Let

a,b,c>1

be pairwise coprime integers. Is every large integer a sum of distinct numbers of the form

a^k b^l c^m

(

k,l,m\ge 0

), none dividing another?

number theoryN/A5 sources

declared open · formalizederdos:124

∀ {D : Finset ℕ}, (∀ d ∈ D, 3 ≤ d) → (∀ᶠ (n : ℕ) in Filter.atTop, n ∈ ∑ d ∈ D, Erdos124.sumsOfDistinctPowers d 0) → 1 ≤ ∑ d ∈ D, (↑d - 1)⁻¹

number theorybase representationsN/A4 sources

declared disproved (Lean) · formalizederdos:125

False ↔ ({x | (Nat.digits 3 x).toFinset ⊆ {0, 1}} + {x | (Nat.digits 4 x).toFinset ⊆ {0, 1}}).HasPosDensity

number theorybase representationsA3670906 sources

declared open · formalized · $250erdos:126

True ↔ ∀ (f : ℕ → ℕ), Erdos126.IsMaximalAddFactorsCard f → Filter.Tendsto (fun n => ↑(f n) / Real.log ↑n) Filter.atTop Filter.atTop

number theorypossible2 sources

declared openerdos:131

Let

F(N)

be the maximal size of

A\subseteq\{1,\ldots,N\}

such that no

a\in A

divides the sum of any nonempty subset of

A\setminus\{a\}

. Estimate

F(N)

. The lower bound

F(N)\gg N^{1/5}

is classical, from constructions of Erdős and Csaba, and every non-dividing set is non-averaging, which gave

F(N)\leq N^{1/4+o(1)}

. The claimed new result is the matching upper bound

F(N)\leq N^{1/5+o(1)}

, obtained by running the Pham-Zakharov density-increment argument one dimension lower through a projective normalization, hence

F(N)=N^{1/5+o(1)}

number theoryA0680632 sources

declared open · formalizederdos:137

sorry ↔ ∀ k ≥ 3, ∀ (n : ℕ), ¬(∏ x ∈ Finset.Ioc n (n + k), x).Powerful

number theoryN/A2 sources

declared proved · $250erdos:144

Erdős problem 144

number theorydivisorsA005279

declared open · formalizederdos:145

True ↔ ∀ α ≥ 0, ∃ β, Filter.Tendsto (fun x => 1 / x * ∑ n ∈ Erdos145.A x, (↑(Erdos145.s (n + 1)) - ↑(Erdos145.s n)) ^ α) Filter.atTop (nhds β)

number theoryA0051172 sources

declared openerdos:148

Erdős problem 148

number theoryunit fractionsA076393 · A006585

declared proved (Lean) · formalizederdos:164

True ↔ ∀ (A : Set ℕ), (∀ a ∈ A, 2 ≤ a) → Erdos1196.IsPrimitive A → ∑' (a : ↑A), 1 / (↑↑a * Real.log ↑↑a) ≤ ∑' (p : ↑{p | Nat.Prime p}), 1 / (↑↑p * Real.log ↑↑p)

number theoryprimitive setsA1372455 sources

declared provederdos:175

Erdős problem 175

number theorybinomial coefficientsN/A

declared disproved (Lean) · formalizederdos:205

False ↔ ∀ᶠ (n : ℕ) in Filter.atTop, Erdos205.IsRepresentable (fun m => Real.log (Real.log ↑m)) n

number theorypossible6 sources

declared disproved (Lean) · formalizederdos:206

False ↔ ∀ᵐ (x : ℝ) ∂MeasureTheory.volume.restrict (Set.Ioi 0), Erdos206.EventuallyGreedy x

number theoryunit fractionsN/A5 sources

declared open · formalizederdos:208

True ↔ ∀ ε > 0, (fun n => ↑(Erdos208.erdos208.s (n + 1)) - ↑(Erdos208.erdos208.s n)) =O[Filter.atTop] fun n => ↑(Erdos208.erdos208.s n) ^ ε

number theoryA005117 · A0762592 sources

declared open · formalizederdos:218

{n | primeGap (n + 1) ≤ primeGap n}.HasDensity (1 / 2)

number theoryprimesA333230 · A333231 · A0641133 sources

declared proved · formalizederdos:219

∅ ∉ Erdos219.primeArithmeticProgressions

number theoryadditive combinatoricsprimesA005115 · A113827 · A1235562 sources

declared proved · $500erdos:220

Erdős problem 220

number theoryA322144

declared proved (Lean) · formalizederdos:221

True ↔ ∃ A, ((fun N => ↑{a | a ∈ A ∧ a ≤ N}.ncard) =O[Filter.atTop] fun N => ↑N / Real.log ↑N) ∧ ∀ᶠ (N : ℕ) in Filter.atTop, ∃ k a, 0 ≤ k ∧ a ∈ A ∧ N = 2 ^ k + a

number theoryadditive basisN/A5 sources

declared openerdos:222

Erdős problem 222

number theorysquaresA001481 · A256435

declared open · formalizederdos:233

(fun N => ∑ n ∈ Finset.range N, ↑(primeGap n) ^ 2) =O[Filter.atTop] fun N => ↑N * Real.log ↑N ^ 2

number theoryprimesA0747413 sources

declared open · formalizederdos:234

True ↔ ∃ f, Continuous f ∧ ∀ (c : NNReal), {n | ↑(primeGap n) / Real.log ↑n < ↑c}.HasDensity (f c)

number theoryprimesN/A2 sources

declared provederdos:235

Erdős problem 235

number theoryN/A

declared open · formalizederdos:236

(fun n => ↑(Erdos236.f n)) =o[Filter.atTop] fun n => Real.log ↑n

number theoryprimesA039669 · A1099252 sources

declared proved (Lean)erdos:237

Erdős problem 237

number theoryprimesN/A4 sources

declared open · formalizederdos:238

True ↔ ∀ c₁ > 0, ∀ c₂ > 0, ∀ᶠ (x : ℝ) in Filter.atTop, ∃ k, c₁ * Real.log x < ↑k ∧ ∃ f m, (∀ (i : Fin k), ↑(f i) ≤ x ∧ f i = Nat.nth Nat.Prime (m + ↑i)) ∧ ∀ (i : Fin (k - 1)), c₂ < primeGap (m + ↑i)

number theoryprimesN/A2 sources

declared proved · formalizederdos:239

True ↔ ∀ (f : ℕ → ℝ), (∀ n ≥ 1, f n = 1 ∨ f n = -1) ∧ (∀ (m n : ℕ), m.Coprime n → f (m * n) = f m * f n) ∧ f 1 = 1 → ∃ L, Filter.Tendsto (fun N => (∑ n ∈ Finset.Icc 1 N, f n) / ↑N) Filter.atTop (nhds L)

number theoryN/A2 sources

declared provederdos:240

Erdős problem 240

number theoryprimesN/A

declared falsifiable · formalizederdos:242

∀ (n : ℕ), 2 < n → ∃ x y z, 1 ≤ x ∧ x < y ∧ y < z ∧ 4 / ↑n = 1 / ↑x + 1 / ↑y + 1 / ↑z

number theoryunit fractionsA073101 · A075245 · A075246 · A075247 · A075248 · A2871162 sources

declared open · formalizederdos:243

∀ (a : ℕ → ℕ), StrictMono a → Filter.Tendsto (fun n => ↑(a n) / ↑(a (n - 1)) ^ 2) Filter.atTop (nhds 1) → (Summable fun x => 1 / ↑(a x)) → ∀ᶠ (n : ℕ) in Filter.atTop, a n = a (n - 1) ^ 2 - a (n - 1) + 1

number theoryA0000582 sources

declared open · formalizederdos:244

True ↔ ∀ C > 1, 0 < {x | ∃ p k, ∃ (_ : Nat.Prime p), p + ⌊C ^ k⌋₊ = x}.lowerDensity

number theoryprimesN/A2 sources

declared proved (Lean) · formalizederdos:246

∀ (a b : ℕ), 2 ≤ a → 2 ≤ b → a.Coprime b → IsAddComplete (Erdos246.Gamma a b)

number theoryN/A5 sources

declared open · formalizederdos:247

True ↔ ∀ (n : ℕ → ℕ), StrictMono n → Filter.limsup (fun k => ↑(n k) / ↑k.succ) Filter.atTop = ⊤ → Transcendental ℚ (∑' (k : ℕ), 1 / 2 ^ n k)

number theoryirrationalityN/A2 sources

declared proved · formalizederdos:248

∃ C > 0, {n | ∀ k ≥ 1, ↑(ArithmeticFunction.cardDistinctFactors (n + k)) ≤ C * ↑k}.Infinite

number theoryN/A2 sources

declared open · formalizederdos:249

True ↔ Irrational (∑' (n : ℕ), ↑n.totient / 2 ^ n)

number theoryirrationalityA2569362 sources

declared proved · formalizederdos:250

(∀ (x : ℝ), HasSum (fun n => ↑((ArithmeticFunction.sigma 1) n) / 2 ^ n) x → Irrational x) ↔ True

number theoryirrationalityA0667662 sources

declared open · formalizederdos:251

True ↔ Irrational (∑' (n : ℕ), ↑(Nat.nth Nat.Prime n) / 2 ^ n)

number theoryirrationalityA0989903 sources

declared open · formalizederdos:252

True ↔ ∀ k ≥ 1, Irrational (Erdos252.erdos_252_sum k)

number theoryirrationalityA227988 · A227989 · A307036 · A359060 · possible2 sources

declared disproved · formalizederdos:253

¬∀ (a : ℕ → ℕ), 0 < a 0 → Erdos253.RepresentsAPs a → Filter.Tendsto (fun n => ↑(a (n + 1)) / ↑(a n)) Filter.atTop (nhds 1) → subsetSums (Set.range a) ∈ Filter.cofinite

number theoryN/A2 sources

declared open · formalizederdos:254

A \subseteq \mathbb{N}

has unbounded dyadic-shell counts and

\sum_{n \in A} \|\theta n\| = \infty

for every

0 < \theta < 1

, must

A

be complete - is every sufficiently large integer a sum of distinct elements of

A

number theoryN/A4 sources

declared openerdos:261

Erdős problem 261

number theoryN/A

declared proved (Lean) · formalizederdos:268

∀ (d : ℕ), (interior {x | ∃ A, A.Infinite ∧ (Summable fun n => 1 / ↑↑n) ∧ x = fun i => ∑' (n : ↑A), 1 / (↑↑n + ↑↑i)}).Nonempty

number theoryN/A5 sources

declared open · formalizederdos:273

True ↔ ∃ c, ∀ (i : c.ι), ∃ p, Nat.Prime p ∧ 5 ≤ p ∧ c.moduli i = Ideal.span {↑(p - 1)}

number theorycovering systemsN/A2 sources

declared proved (Lean) · formalizederdos:275

∀ (r : ℕ) (a : Fin r → ℤ) (n : Fin r → ℕ), (∃ k, ∀ x ∈ Set.Ico k (k + 2 ^ r), ∃ i, x ≡ a i [ZMOD ↑(n i)]) → ∀ (x : ℤ), ∃ i, x ≡ a i [ZMOD ↑(n i)]

number theorycovering systemsN/A5 sources

declared open · formalizederdos:276

True ↔ ∃ a, Erdos276.IsLucasSequence a ∧ (∀ (k : ℕ), (a k).Composite) ∧ ∀ n > 1, ∃ k, n.gcd (a k) = 1

number theorycovering systemsN/A2 sources

declared proved · formalizederdos:277

True ↔ ∀ (c : ℝ), ∃ n, ↑((ArithmeticFunction.sigma 1) n) > c * ↑n ∧ ∀ (m : StrictCoveringSystem ℤ), ∃ i, ↑n ∉ m.moduli i

number theorycovering systemsN/A2 sources

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