FormalConjectures/ErdosProblems/643.lean
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2 declarations, 2 contain sorry, 0 declared as axioms
Erdős Problem 643
References:
- erdosproblems.com/643
- [Fu84] F"uredi, Z., Hypergraphs in which all disjoint pairs have distinct unions. Combinatorica (1984), 161--168.
- [PiVe09] Pikhurko, Oleg and Verstra"{e}te, Jacques, The maximum size of hypergraphs without generalized 4-cycles. J. Combin. Theory Ser. A (2009), 637--649.
Imports (1)
- theorem
Erdos643.erdos_643.parts.iDocumented declaration: i sorry line 47 sourceSource documentation
Let $f(n;t)$ be minimal such that if a $t$-uniform hypergraph on $n$ vertices contains at least $f(n;t)$ edges then there must be four edges $A,B,C,D$ such that $$A\cup B= C\cup D$$ and $$A\cap B=C\cap D=\emptyset.$$ Estimate $f(n;t)$ - in particular, is it true that for $t\geq 3$ $$f(n;t)=(1+o(1))\binom{n}{t-1}?$$
depends on sorry what this means
Statement uses:
Nat,Real,sorryAx,Bool.false,LE.le,OfNat.ofNat,Asymptotics.IsEquivalent,Filter.atTop,HAdd.hAdd, Hypergraph.extremalNumber,Finset,Fin,Not, Finset.HasRepeatedDisjointUnionProof uses:
Lean.Name,Lean.Name.num,Lean.Name.str,Lean.Name.anonymous26 instances, coercions and auxiliary constants left out.
Tactic trace: 1 steps
Open to load the checked before-and-after goal states.
theorem erdos_643.parts.i : let f : ℕ → ℕ → ℝ := answer(sorry) … - theorem
Erdos643.erdos_643.parts.iiIs it true that $f(n;t)=(1+o(1))\binom{n}{t-1}$ for $t\geq 3$? sorry line 58 sourceSource documentation
Is it true that $f(n;t)=(1+o(1))\binom{n}{t-1}$ for $t\geq 3$?
depends on sorry what this means
Statement uses:
Iff,True,Nat,LE.le,OfNat.ofNat,Asymptotics.IsEquivalent,Real,Filter.atTop,HAdd.hAdd, Hypergraph.extremalNumber,Finset,Fin,Not, Finset.HasRepeatedDisjointUnion,Nat.choose,HSub.hSubProof uses:
sorryAx,Lean.Name,Bool.false,Lean.Name.num,Lean.Name.str,Lean.Name.anonymous30 instances, coercions and auxiliary constants left out.
Tactic trace: 1 steps
Open to load the checked before-and-after goal states.
theorem erdos_643.parts.ii : answer(sorry) ↔ ∀ t : ℕ, 3 ≤ t → (fun n ↦ ((Hypergraph.extremalNumber n t (fun H ↦ ¬ H.HasRepeatedDisjointUnion) + 1 : ℕ) : ℝ)) ~[atTop] (fun n ↦ (n.choose (t - 1) : ℝ)) := by …Mentions: Hypergraph.extremalNumber