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# Blackboard bold

Please do not rely on any information it contains.

A blackboard bold (double struck, open face) letter is an uppercase alphabetic character of the Latin alphabet that denotes an important set of numbers. Although the entire alphabet is available for this purpose in LaTeX and many of them have been assigned at one time or another, only a few letters are regularly used as blackboard bold in number theory, namely
 ℕ
for natural numbers,
 ℤ
for rational integers,
 ℚ
for rational numbers,
 𝔸
for algebraic numbers,
 ℝ
for real numbers, and
 ℂ
for complex numbers. Many texts also use
 𝔽p
to denote a finite field with
 p
elements (
 p
generally specified to be a prime number).

## LaTeX

LaTeX text style
Code Result
$\scriptstyle \mathbb{N},\, \N$ ${\displaystyle \scriptstyle \mathbb {N} ,\,\mathbb {N} }$
$\scriptstyle \mathbb{Z},\, \Z$ ${\displaystyle \scriptstyle \mathbb {Z} ,\,\mathbb {Z} }$
$\scriptstyle \mathbb{Q},\, \Q$ ${\displaystyle \scriptstyle \mathbb {Q} ,\,\mathbb {Q} }$
$\scriptstyle \mathbb{R},\, \R$ ${\displaystyle \scriptstyle \mathbb {R} ,\,\mathbb {R} }$
$\scriptstyle \mathbb{C},\, \C$ ${\displaystyle \scriptstyle \mathbb {C} ,\,\mathbb {C} }$

LaTeX display style
Code Result
$\mathbb{N}, \N$ ${\displaystyle \mathbb {N} ,\mathbb {N} }$
$\mathbb{Z}, \Z$ ${\displaystyle \mathbb {Z} ,\mathbb {Z} }$
$\mathbb{Q}, \Q$ ${\displaystyle \mathbb {Q} ,\mathbb {Q} }$
$\mathbb{R}, \R$ ${\displaystyle \mathbb {R} ,\mathbb {R} }$
$\mathbb{C}, \C$ ${\displaystyle \mathbb {C} ,\mathbb {C} }$
LaTeX text style
Code Result
{{math|{{mathbb|N|tex}},\, {{sym|N|tex}}|$}} ${\displaystyle \scriptstyle \mathbb {N} ,\,{\mathbb {N} }}$ {{math|{{mathbb|Z|tex}},\, {{sym|Z|tex}}|$}} ${\displaystyle \scriptstyle \mathbb {Z} ,\,{\mathbb {Z} }}$
{{math|{{mathbb|Q|tex}},\, {{sym|Q|tex}}|$}} ${\displaystyle \scriptstyle \mathbb {Q} ,\,{\mathbb {Q} }}$ {{math|{{mathbb|R|tex}},\, {{sym|R|tex}}|$}} ${\displaystyle \scriptstyle \mathbb {R} ,\,{\mathbb {R} }}$
 𝟡, 𝟡