Schubert (1949) showed that every knot can be uniquely decomposed (up to the order in which the decomposition is performed) as a knot sum of a class of knots known as prime knots, which cannot themselves be further decomposed (Livingston 1993, p. 5; Adams 1994, pp.
The Moors were Muslim inhabitants of the Maghreb, the Iberian Peninsula, Sicily, and Malta during the Middle Ages.
The Moors. Muslim warriors crossed the narrow Strait of Gibraltar in the eighth century to invade the Iberian Peninsula at the southwest corner of Europe. Muslims controlled part or most of present-day Spain and Portugal for the next 800 years.