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.
Highland continents â or terrae â are areas of topographically unstable terrain, with high peaks and valleys. They resemble highlands on Earth, but the term is applied to much larger areas on other planets. They can be found on Venus, [6] Mercury, Mars and the Moon.