# Euclid

## Euclid (Greek mathematician)

Euclid (yōō´klĬd), fl. 300 BC, Greek mathematician. Little is known of his life other than the fact that he taught at Alexandria, being associated with the school that grew up there in the late 4th cent. BC He is famous for his Elements, a presentation in thirteen books of the geometry and other mathematics known in his day. The first six books cover elementary plane geometry and have served since as the basis for most beginning courses on this subject. The other books of the Elements treat the theory of numbers and certain problems in arithmetic (on a geometric basis) and solid geometry, including the five regular polyhedra, or Platonic solids. A few modern historians have questioned Euclid's authorship of the Elements, but he is definitely known to have written other works, most notably the Optics.

The great contribution of Euclid was his use of a deductive system for the presentation of mathematics. Primary terms, such as point and line, are defined; unproved assumptions, or postulates, regarding these terms are stated; and a series of statements are then deduced logically from the definitions and postulates. Although Euclid's system no longer satisfies modern requirements of logical rigor, its importance in influencing the direction and method of the development of mathematics is undisputed.

One consequence of the critical examination of Euclid's system was the discovery in the early 19th cent. that his fifth postulate, equivalent to the statement that one and only one line parallel to a given line can be drawn through a point external to the line, can not be proved from the other postulates; on the contrary, by substituting a different postulate for this parallel postulate two different self-consistent forms of non-Euclidean geometry were deduced, one by Nikolai I. Lobachevsky (1826) and independently by János Bolyai (1832) and another by Bernhard Riemann (1854).

See D. Berlinski, The King of Infinite Space: Euclid and His Elements (2013).

The Columbia Encyclopedia, 6th ed. Copyright© 2018, The Columbia University Press.

## Euclid: Selected full-text books and articles

The King of Infinite Space: Euclid and His Elements By David Berlinski Basic Books, 2013
The Great Mathematicians By Herbert Westren Turnbull New York University Press, 1961
Librarian's tip: Chap. III "Alexandria: Euclid, Archimedes, and Apollonius"
The Infinite in the Finite By Alistair Macintosh Wilson Oxford University Press, 1995
Librarian's tip: Chap. 10 "The Elements of Euclid"
Ancient Mathematics By S. Cuomo Routledge, 2001
Librarian's tip: "Euclid" begins on p. 88
Studies in the History and Methods of the Sciences By Arthur David Ritchie University Press, 1958
Librarian's tip: Chap. III "Elements of Geometry: Euclid"
History of the Sciences in Greco-Roman Antiquity By Arnold Reymond; Ruth Gheury De Bray Biblo and Tannen, 1963
The Art of the Infinite: The Pleasures of Mathematics By Robert Kaplan; Ellen Kaplan Oxford University Press, 2003
Librarian's tip: Chap. Five "Euclid Alone"
Makers of Science: Mathematics, Physics, Astronomy By Ivor B. Hart Oxford University Press; H. Milford, 1923
Librarian's tip: "Euclid" begins on p. 34
A Concise History of Mathematics By Dirk J. Struik Dover, 1948 (2nd Rev. edition)
Librarian's tip: Discussion of Euclid begins on p. 58
History of Western Philosophy By Bertrand Russell Routledge, 2004
Librarian's tip: Chap. 24 "Early Greek Mathematics and Astronomy"
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