arityArity2002-08-28 21:49:252002-08-28 21:49:25Definitionunarybinary% this is the default PlanetMath preamble. as your knowledge
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%\PMlinkescapeword{theory}The \emph{arity} of something is the number of arguments it takes. This is usually applied to functions: an $n$-ary function is one that takes $n$ arguments. \emph{Unary} is a synonym for $1$-ary, and binary for $2$-ary.