U+211D DoubleStruck Capital R
U+211D was added in Unicode version 1.1 in 1993. It belongs to the block
This character is a Uppercase Letter and is commonly used, that is, in no specific script. The character is also known as the set of real numbers.
The glyph is a font version of the glyph
The Wikipedia has the following information about this codepoint:
In mathematics, a real number is a number that can be used to measure a continuous onedimensional quantity such as a distance, duration or temperature. Here, continuous means that pairs of values can have arbitrarily small differences. Every real number can be almost uniquely represented by an infinite decimal expansion.
The real numbers are fundamental in calculus (and more generally in all mathematics), in particular by their role in the classical definitions of limits, continuity and derivatives.
The set of real numbers is denoted R or $R$ and is sometimes called "the reals". The adjective real, used in the 17th century by René Descartes, distinguishes real numbers from imaginary numbers such as the square roots of −1.
The real numbers include the rational numbers, such as the integer −5 and the fraction 4 / 3. The rest of the real numbers are called irrational numbers. Some irrational numbers (as well as all the rationals) are the root of a polynomial with integer coefficients, such as the square root √2 = 1.414...; these are called algebraic numbers. There are also real numbers which are not, such as π = 3.1415...; these are called transcendental numbers.
Real numbers can be thought of as all points on a line called the number line or real line, where the points corresponding to integers (..., −2, −1, 0, 1, 2, ...) are equally spaced.
Conversely, analytic geometry is the association of points on lines (especially axis lines) to real numbers such that geometric displacements are proportional to differences between corresponding numbers.
The informal descriptions above of the real numbers are not sufficient for ensuring the correctness of proofs of theorems involving real numbers. The realization that a better definition was needed, and the elaboration of such a definition was a major development of 19thcentury mathematics and is the foundation of real analysis, the study of real functions and realvalued sequences. A current axiomatic definition is that real numbers form the unique (up to an isomorphism) Dedekindcomplete ordered field. Other common definitions of real numbers include equivalence classes of Cauchy sequences (of rational numbers), Dedekind cuts, and infinite decimal representations. All these definitions satisfy the axiomatic definition and are thus equivalent.
Representations
System  Representation 

Nº  8477 
UTF8  E2 84 9D 
UTF16  21 1D 
UTF32  00 00 21 1D 
URLQuoted  %E2%84%9D 
HTML hex reference  ℝ 
Wrong windows1252 Mojibake  â„ 
HTML named entity  ℝ 
HTML named entity  ℝ 
alias  the set of real numbers 
L^{A}T_{E}X  \mathbb{R} 
Related Characters
Confusables
Elsewhere
Complete Record
Property  Value 

1.1 (1993)  
DOUBLESTRUCK CAPITAL R  
DOUBLESTRUCK R  
Letterlike Symbols  
Uppercase Letter  
Common  
Left To Right  
Not Reordered  
font  


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✘  
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Any  
✔  
✘  
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✘  
✔  
✔  
✘  
✘  
0  
0  
0  
✘  
None  
—  
NA  
Other  
—  
✘  
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✔  
✘  
Yes  
Yes  


No  


No  
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✘  
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✘  
Upper  
✘  
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Alphabetic Letter  
✘  
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✘  
✘  
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None  
neutral  
Not Applicable  
—  
No_Joining_Group  
Non Joining  
Alphabetic  
none  
not a number  


R 