ℝ

See also: Appendix:Variations of "r"

ℝ U+211D, ℝ DOUBLE-STRUCK CAPITAL R ← ℜ [U+211C] Letterlike Symbols ℞ → [U+211E]

Translingual

Etymology

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

ℝ

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

Derived terms

• ℝ-order tree (English)