Name this mathematician who created the parallel postulate in his treatise on geometry, The Elements—an ancient Greek.
This man's namesake orchard consists of one-dimensional trees planted at lattice points in the plane. His namesake metric is the L-P metric with p equaling two, which is also the "usual" metric. His namesake algorithm subtracts integer multiples of one given number from another to compute the two numbers' greatest common factor. He also names geometries that assume that given a line and a point not on it, there is exactly one line that does not intersect the given line. His most famous work started from five axioms and five postulates. Name this mathematician who created the parallel postulate in his treatise on geometry, The Elements—an ancient Greek.
This man's namesake orchard consists of one-dimensional trees planted at lattice points in the plane.
{Euclid} of Alexandria [or Eukleíd?s]