identity element
Noun

identity element (plural identity elements)

  1. (algebra) An element of an algebraic structure which when applied, in either order, to any other element via a binary operation yields the other element.
    • 1990, Daniel M. Fendel, Diane Resek, Foundations of Higher Mathematics, Volume 1, Addison-Wesley, page 269 ↗,
      Therefore the number 0 is not considered an identity element for subtraction, even though x - 0 = x for all x, since 0 - x\ne x.
    • 2003, Houshang H. Sohrab, Basic Real Analysis, Birkhäuser, page 17 ↗,
      Let (G,\cdot) be a group. Then the identity element e\in G is unique. […]
      Proof. If e and e' are both identity elements, then we have ee' = e since e' is an identity element, and ee' = e' since e is an identity element. Thus
      e = ee' = e'.
    • 2015, Martyn R. Dixon, Leonid A. Kurdachenko, Igor Ya. Subbotin, An Introduction to Essential Algebraic Structures, Wiley, page 41 ↗,
      Sometimes, to avoid ambiguity, we may use the notation e_M for the identity element of M.
      If multiplicative notation is used then we use the term identity element, and often use the notation 1, or 1_M, for the neutral element e.
Synonyms
  • (element that when applied with a binary operation leaves any other element unchanged) identity, neutral element
Related terms Translations
  • Italian: elemento neutro
  • Russian: то́ждество
  • Spanish: elemento neutro



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