Problems

Under smoothness, positivity, decay and score assumptions, are all steady solutions of the Coulomb Vlasov-Maxwell-Landau system on T^3 × R^3 necessarily spatially uniform Maxwellians?

Lassak conjectured that a reduced planar convex body of thickness Δ has area at most (π/4)Δ^2, the value for the disc. False: an explicit reduced body of thickness 1 has area 0.786215… > π/4 = 0.785398…, given by a closed-form support…

Is computing a Kemeny-optimal aggregate ranking NP-hard when the input consists of exactly three complete rankings? Hardness was known for every even n ≥ 4; three voters was the minimal open case, and n = 2 is polynomial-time solvable.

VibeMathed records no statement for this problem. See erdosproblems.com for the original.

For the switch-walk-switch lamplighter walk on Z_2 wr T_d, prove the sharp asymptotic p_2n(e,e) = ρ_d^2n exp[-(π^2 (log(d-1))^2 + o(1)) n/log^2 n] with ρ_d = frac2√d-1d.

Are ICC property (T) groups remembered by their von Neumann algebras - if L(Γ) ≅ L(Λ) for such groups, must Γ ≅ Λ? A counterexample refutes Connes' conjecture that these groups are uniquely determined by their group von Neumann algebras.

VibeMathed records no statement for this problem. See erdosproblems.com for the original.

Conjectured upper bound on how many pairs among n points in the plane can be exactly one unit apart.

VibeMathed records no statement for this problem. See erdosproblems.com for the original.

VibeMathed records no statement for this problem. See erdosproblems.com for the original.

Must every connected graph satisfy the proposed upper bound on its independence number in terms of residue and largest induced-bipartite-subgraph order? The family overlineK_2r+1 ∨ (K_r sqcup K_r) violates it for every r ≥ 3.

How large must y(ε, n) be so that every interval (x, x+y) contains at most ε y integers having a divisor in (n, 2n)? The candidate proof gives the sharp fixed-ε order y = Θ_ε(n), uniformly in the translate.

Must every graph with n vertices and δ n^2 edges contain large subgraphs in which every two edges lie on specified short cycles? A dense high-girth construction refutes the statement when δ may shrink with n.

The Kajitani–Ueno–Miyano conjecture asserts that every finite uniformly dense matroid has a cyclic basis ordering. The conjecture is proved for all matroids of rank three. The new result establishes the previously unresolved divisible…

Chromatic quasisymmetric functions of natural unit interval graphs were conjectured to have log-concave coefficients in the elementary basis. A connected 13-vertex example refutes it: for the Hessenberg function…

For an even cycle of size N and depth p with 2p + 2 ≤ N, is the optimal QAOA approximation ratio for MaxCut exactly 2p+1/2p+2, as Farhi, Goldstone and Gutmann conjectured?

The Huneke–Wiegand Conjecture: Let R be a one-dimensional Gorenstein local domain, and let M be a finitely generated, non-zero, torsion-free R-module. If the tensor product M ⊗_R M^* is torsion-free, then M is a projective (hence free)…

For an arrangement of n hyperplanes in P^3_C with ℓ intersection lines and p intersection points where at least three hyperplanes meet, the refined form of Purdy's inequality expects p - ℓ + n + 2 ≥ 0. An explicit arrangement built from…

VibeMathed records no statement for this problem. See erdosproblems.com for the original.

Simon conjectured that every skeleton of a simplex is extendably shellable. False: for every d ≥ 3 there is a pure d-dimensional shellable simplicial complex that is not shelling completable.