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U+211D, ℝ
DOUBLE-STRUCK CAPITAL R

[U+211C]
Letterlike Symbols
[U+211E]

Translingual

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Etymology

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In Stetigkeit und irrationale Zahlen (1872) Richard Dedekind uses R to denote rational numbers and ℜ to denote real numbers. The usage of blackboard bold dates to the 1960s.

Noun

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  1. (mathematics) The set of real numbers.
  2. (mathematics) This set, equipped with any of its standard structure; the real line.

Derived terms

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