U00AC

U+00AC, commonly called Not Sign, is a typographic symbol used to denote negation in logic and related disciplines. It is encoded in the Unicode standard at code point U+00AC (decimal 172) and belongs to the Latin-1 Supplement block. The official Unicode name is Not Sign, and its general category is Symbol, Other.

In mathematical logic and formal notation, the Not Sign is used as a unary operator to indicate negation, as in ¬P meaning “not P.” It appears frequently in textbooks and theoretical contexts. In many programming languages, negation is expressed with different syntax (such as not, !, or ~), so the glyph itself is less common in everyday code but remains a standard symbol in formal writing and proofs.

Encoding and typography: In HTML, the character can be written as ¬ or as ¬. In LaTeX, the symbol is produced with \lnot or \neg in math mode; these commands yield a glyph similar to the Not Sign. Font rendering of the character can vary between typefaces, but the shape generally resembles a left-leaning, small wedge or an inverted L, designed to be distinct from other symbols.

See also: Logical negation, Not Sign (Unicode), Negation in logic.