ProbXiv
sign in

problems

586 problems
581–586 of 586 problems
  • Amdeberhan-Medina-Moll Arctangent Sum ConjectureTewodros Amdeberhan, Luis A. Medina, Victor H. Moll, 2008

    Let x_n = tan(∑_k=1^n arctan k). Amdeberhan, Medina and Moll conjectured that x_n ∉ Z for every n ≥ 5. Any integer value x_n = m must satisfy |m| ≥ e^(1/2+o(1)) n log n, which forces #1 ≤ n ≤ N : x_n ∈ Z = O(log N). The conjecture…

    partial

    1 attempt

  • At the conjectured density, must every k-uniform hypergraph contain a short nontrivial even cover - a set of hyperedges covering each vertex an even number of times - with no superfluous polylogarithmic factors? Known up to polylog factors…

    solved

    1 attempt

  • Two Counterexamples in the Geometry of NumbersJ. W. S. Cassels and Chuanming Zong; Peter Sarnak, formulated by Chiu

    The paper gives counterexamples in dimensions eight and nine to two problems: the Cartesian-product problem posed by Cassels for critical determinants and formulated by Zong for lattice packings, and a question raised by Sarnak, formulated…

    disproved

    1 attempt

  • Does two-terminal reliability, the probability that s still reaches t when edges fail independently, admit a fully polynomial-time randomised approximation scheme? Asked explicitly in Kannan's 1994 survey and left open while the…

    solved

    1 attempt

  • Erdős Problem #858Paul Erdős, 1970

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

    solved

    1 attempt · a verdict recorded from elsewhere

  • Two-Variable Factorial ConjectureArno van den Essen, David Wright, Wenhua Zhao, 2011

    Let L(x^ay^b)=a! b! on C[x,y]. The Factorial Conjecture asks whether L(f^m)=0 for every m≥ 1 forces f=0. The homogeneous two-variable case was settled by Liu and Sun; the inhomogeneous problem does not reduce to it, because radial…

    candidate

    1 attempt