0x211D

0x211D refers to the Unicode code point U+211D, which corresponds to the character ℝ. Its official Unicode name is BLACK-LETTER CAPITAL R, and it is part of the Letterlike Symbols block used for mathematical notation. In many fonts the glyph appears in a blackletter or double-struck style and is commonly associated with the set of real numbers.

In mathematics, ℝ is used to denote the real numbers and related concepts. It appears in expressions such as ℝ^n for real n-dimensional space or ℝ^+ for the set of positive real numbers. The symbol is widely recognized across disciplines including analysis, algebra, and applied sciences, and is often contrasted with related symbols for other number sets such as ℕ (natural numbers), ℤ (integers), ℚ (rationals), and ℂ (complex numbers).

Rendering and font considerations are important for ℝ. While the symbol is supported in most modern fonts, its exact appearance varies; some fonts render it as a true blackboard-bold or ornate blackletter style, while others render it as a more standard uppercase R with stylistic flourishes. Availability can depend on the font and software in use.

Encoding and representation: U+211D is the canonical code point. In document or web contexts, it can be written as a numeric character reference, for example using ℝ in HTML or ℝ in decimal form. Many programming languages also support Unicode escapes such as \u211D.

See also: related mathematical symbols for number sets, including ℕ (U+2115), ℤ (U+2124), ℚ (U+211A), and ℂ (U+2102).