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.
Depiction of the Moors in Iberia, from The Cantigas de Santa Maria. In 711 the Islamic Moors of Arab and Berber descent in North Africa crossed the Strait of Gibraltar onto the Iberian Peninsula, and in a series of raids they conquered Visigothic Christian Hispania.