더블 스트라크 캐피탈 R ℝ

The set of real numbers ℝ can be best understood as all the finite and infinite decimal fractions. ℝ is the first known uncountable set. The term ‘real‘ comes from the Latin word ‘realis,‘ meaning ‘actual‘ or ‘real.‘

By the 3rd century, it became clear that rational numbers were not sufficient for representing distances in geometry. A comprehensive theory of real numbers emerged in the 19th century with the development of mathematical analysis.

The sets ℕ , ℤ , ℚ , ℝ , ℂ are often written in bold font (for example, in the works of Nicolas Bourbaki) or as double-struck letters on blackboards and manuscripts. American mathematicians introduced the usage of double-struck font in printed texts, and it became popularized with the famous textbook on complex analysis by Gunning and Rossi, published in 1965.

‘더블 스트라크 캐피탈 R‘ 기호는 ‘수식 기호 문자‘ 블록의 ‘글자 모양의 기호‘ 서브블록에 포함되어 있으며 1993년에 Unicode 버전 1.1의 일부로 승인되었습니다.