An elementary proof of de Finettis Theorem

A sequence of random variables is called exchangeable if the joint distribution of the sequence is unchanged by any permutation of the indices. De Finettis theorem characterizes all ${0,1}$-valued exchangeable sequences as a mixture of sequences of independent random variables. We present an new, elementary proof of de Finettis Theorem. The purpose of this paper is to make this theorem accessible to a broader community through an essentially self-contained proof.