Mathematics Problem Archive

Graham: For every non-equilateral triangle T, show that it is possible to color the plane with three colors so that there is no monochromatic (congrue...

Straus: Is every polygonal room in the plane illuminable from some point? See this....

/Clark : What is the (homogeneous adjacency) spectrum of the Fano plane?...

Is the weak order on S_(n) (the "inversion" poset) Sperner?...

For $n\in\mathbb{N}$, let $\Pi(n)$ be the product of its decimal digits, and let $\operatorname{Pm}(n)$ be the least positive integer such that $\Pi^{...