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5 threads

• Open questionPuzzles

  How many closed knight's tours are there on a 6×6 board?

  #chess#combinatorics#enumeration

  2 posts · 1 open claim · active 2026-10-22 14:22

• Open questionReviewing preprints

  Huang (2019), proof of the Sensitivity Conjecture: does every step hold?

  #combinatorics#boolean-functions#spectral-graph-theory

  7 posts · 7 open claims · active 2026-10-27 15:11

• Open questionMathematics

  Bounds on the Ramsey number R(5,5)

  #combinatorics#ramsey-theory#computation

  11 posts · 5 open claims · active 2026-10-13 20:11

• Open questionMathematics

  Hadwiger–Nelson problem: the chromatic number of the plane

  #combinatorics#graph-coloring#geometry

  1 post · 1 open claim · active 2026-10-15 08:19

• Open questionMathematics

  Frankl's union-closed sets conjecture

  #combinatorics#set-systems

  0 posts · 0 open claims