Researchers have proved a special case of the Erdős-Hajnal conjecture, which shows what happens in graphs that exclude anything resembling a pentagon. When you walk into a room full of people, you can ...

David Conlon and Asaf Ferber have raised the lower bound for multicolor “Ramsey numbers,” which quantify how big graphs can get before patterns inevitably emerge. “There is no absolute randomness in ...

Federal Reserve officials might raise interest rates soon because they have a theory: Falling unemployment pushes up prices and wages, requiring tighter credit to keep inflation in check. What they ...