Weierstrass p

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This article is about the typographical character. For the elliptic function, see Weierstrass's elliptic function.
Weierstrass p
Weierstrass p

In mathematics, the Weierstrass p (℘, ), also called pe, is used for Weierstrass's elliptic functions. It is occasionally used for the power set,[1] although for that purpose a cursive capital, rather than lower-case, p is more widespread. It is named after the German mathematician Karl Weierstrass.

Its Unicode code point is U+2118 script capital p (HTML ℘ · ℘). The naming is incorrect, because it is always a lowercase letter, but this error is not corrected in later versions in order to keep the Unicode standard stable.[2] The TeX code for this character is \wp.

Starting with Unicode 3.0.1, a separate, capital symbol is available for power set, namely U+1D4AB 𝒫 MATHEMATICAL SCRIPT CAPITAL P (HTML 𝒫), which is available as 𝒫 in HTML5.[3][4] As of 2009, only a few specialized OpenType fonts support this code point.


  1. ^ de Haan, Lex; Koppelaars, Toon (2007), "Chapter 2 — Set Theory: Introduction", Applied Mathematics for Database Professionals, Apress, p. 35, ISBN 978-1-59059-745-3 
  2. ^ In Latex it is denoted \wp. "Unicode Technical Note #27: Known Anomalies in Unicode Character Names". Unicode Consortium. 2006-05-08. Retrieved 2011-06-11. 
  3. ^ "8 The HTML syntax — HTML5". W3.org. Retrieved 2014-08-11. 
  4. ^ "Unicode Character 'MATHEMATICAL SCRIPT CAPITAL P' (U+1D4AB)". Fileformat.info. Retrieved 2010-03-15.