<mathematics> The fixed point of a function, f is any value, x for which f x = x. A function may have any number of fixed points from none (e.g. f x = x+1) to infinitely many (e.g. f x = x). The fixed point combinator, written as either "fix" or "Y" will return the fixed point of a function.
See also least fixed point.
<programming> A number representation scheme where a number R is represented by an integer N such that R=N*B, where B is the (assumed) base of the representation.
On computers with no floating-point unit fixed-point calculations can be significantly faster as all the operations are basically integer operations. Apart from that, fixed-point representation has the advantage of having uniform density, i.e., the smallest resolvable difference of the representation is B throughout the representable range, in sharp contrast to floating-point representations.