Galois theory

/ˈɡælwɑ ˈθi.əɹi/

noun

The branch of mathematics dealing with Galois groups, Galois fields, and polynomial equations. It provides a link between field theory and group theory: it permits certain problems in the former to be reduced to the latter, which in some respects is simpler and better understood.

Meanings

nounGalois theory (usually uncountable, plural Galois theories)

plural Galois theories

  1. uncountableusuallyfield theoryalgebraThe branch of mathematics dealing with Galois groups, Galois fields, and polynomial equations. It provides a link between field theory and group theory: it permits certain problems in the former to be reduced to the latter, which in some respects is simpler and better understood.

    1992, Journal of Contemporary Mathematical Analysis, Volume 27, Allerton Press, page 4, Though often our results are prompted by the classical or parallel Galois theories, their proofs are completely different and are based on the set-theoretical approach.

    3 more examples

    In this chapter we present the Galois theory which may be described as the analysis of field extensions by means of automorphism groups.

    1989, G. Karpilovsky, Topics in Field Theory, North-Holland, page 299

    The Galois theory of noncommutative rings is a natural outgrowth of the Galois theory of fields.

    1989, Donald S. Passman, Infinite Crossed Products, Academic Press, page 297

    Classical Galois theory has developed a number of extensions and ramifications into more specific theories, which combine it with other areas of mathematics or restate its main problems in different situations. Three of the most important are geometric Galois theory, differential Galois theory, and Lie Galois theory, all of which have undergone very rapid development in recent years.

    2003, “Introduction”, in Leila Schneps, editor, Galois Groups and Fundamental Groups, Cambridge University Press, page ix

Origin

  1. Frenchthéorie de Galois
  2. EnglishGalois theory

Standardly constructed calque of French théorie de Galois (which was used as a section heading in 1870, Camille Jordan, Traité des substitutions et des équations algébriques). First appeared in print in 1893, Bulletin of the New York Mathematical Society. Ultimately, named after French mathematician Evariste Galois (1811-1832), who first developed the theory to explore how the roots of a given polynomial equation relate to each other.

Full word history & related roots →

Translations

French théorie de Galois
  • théorie de Galoisbranch of mathematics
German Galoistheorie
  • Galoistheoriebranch of mathematics
Italian teoria di Galois
  • teoria di Galoisbranch of mathematics
Polish teoria Galois
  • teoria Galoisbranch of mathematics
Cite this entry
APA

Galois theory. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/Galois%20theory

MLA

“Galois theory.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/Galois%20theory. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “Galois theory,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/Galois%20theory.

Source: Galois theory on Wiktionary, CC BY-SA 4.0.