On Normalized Entropy and the Extensions of a Positive-Definite Function J. Chover Indiana University Mathematics Journal 1961 text pdf 10.1512/iumj.1961.10.10059 10.1512/iumj.1961.10.10059 en Indiana Univ. Math. J. 10 (1961) 927 - 945 state-of-the-art mathematics http://iumj.org/access/