- Algebra is a branch of mathematics sibling to geometry, analysis (calculus), number theory, combinatorics, etc. Although algebra has its roots in numerical domains such as the reals and the complex numbers, in its full generality it differs from its siblings in serving no specific mathematical domain. Whereas geometry treats spatial entities, analysis continuous variation, number theory integer arithmetic, and combinatorics discrete structures, algebra is equally applicable to all these and other mathematical domains.
- Star Tales - Equuleus (ianridpath.com)
This insignificant constellation, second-smallest in the sky, was one of the 48 constellations listed by the Greek astronomer Ptolemy in the second century AD. It was unknown to Aratus 400 years earlier, and its invention is often attributed to Ptolemy. In the Almagest he called it Ἵππου Προτομή (Hippou Protome), the forepart of a horse; Equuleus is a later Latin name.
stanford encyclopedia of philosophy of