The story
Proposed by Danish mathematician Bent Fuglede in 1974
Etymology from Wiktionary, CC BY-SA 4.0.
Fuglede's conjecture
Today it means: The conjecture that every domain of ℝᵈ (i.e. subset of ℝᵈ with positive finite Lebesgue measure) is a spectral set if and only if it tiles ℝᵈ by translation. Full definition →