1. <logic> One of the simple function-building operations of recursive function theory. Given the one-place functions f(x) and g(x), composition allows us to create function h thus: h(x) = f(g(x)). More generally, if f is an m-place, f(x1...xm), and there is a series of n-place functions g, g(x1...xn), then we can create the n-place function h by composition: h(x1...xn) = f(g(x1...xn),...,gm(x1...xn)). Also called substitution.
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