(Greek letter). 1. /micro/ prefix denoting division by 10^6, e.g. mu m (micrometre, a millionth part of a metre). Sometimes written as a ' u' , the ASCII character nearest in appearance. 2. AThemATics> /myoo/ In the theory of functions, mu x . E denotes the least value of x for which E = x, i.e. the {least fixed point} of the function x . E. The {recursive} function mu f . H f sATisfies (and is defined by) the equATion mu f . H f = H (mu f . H f) An alternATive notATion for the same function is fix H = H (fix H) See fixed point combinATor. 3. ATabase> multiple value. [Jargon File] (1995-10-30)