  A Sidon set is a set of the positive integers such that the sums of two pairs
is not repeated. I. Ruzsa gave a probabilistic construction of an infinite
Sidon set. In this work we present the details of a simplified proof of this
construction as suggested in a paper of I. Ruzsa and J. Cilleruelo (Real and
-padic Sidon sequences, Acta Sci. Math (Szeged) 70 (2004), 505-510).
