a1 Department of Mathematics Gumma University Aramaki-cho 4, Maebashi 371, Japan
We give a transcendence measure of special values of functions satisfying certain functional equations. This improves an earlier result of Galochkin, and gives a better upper bound of the type for such a number as an S-number in the classification of transcendental numbers by Mahler.
(Received February 26 1990)
(Revised August 28 1990)
1991 Mathematics subject classification (Amer. Math. Soc.)