Separating set

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In mathematics a set of functions S from a set D to a set C is called a separating set for D or said to separate the points of D if for any two distinct elements x and y of D, there exists a function f in S so that f(x) ≠ f(y).[1]

Separating sets can be used to formulate a version of the Stone-Weierstrass theorem for real-valued functions on a compact Hausdorff space X, with the topology of uniform convergence. It states that any subalgebra of this space of functions is dense if and only if it separates points. This is the version of the theorem originally proved by Marshall H. Stone.[1]



  1. ^ a b Carothers, N. L. (2000), Real Analysis, Cambridge University Press, pp. 201–204, ISBN 9781139643160 .