least fixed point
least fixed point
(mathematics)If f is recursive, we can represent it as
f = fix F
where F is some higher-order function and
fix F = F (fix F).
The standard denotational semantics of f is then given bythe least fixed point of F. This is the least upper boundof the infinite sequence (the ascending Kleene chain)obtained by repeatedly applying F to the totally undefinedvalue, bottom. I.e.
fix F = LUB bottom, F bottom, F.
The least fixed point is guaranteed to exist for acontinuous function over a cpo.