Even-Odd Set Partitions, Saddle-Point Method and Wyman Admissibility
Résumé
The reciprocal of the generating function of the Bell numbers enumerates the difference between numbers of set partitions with even and odd number of blocks. The asymptotic behaviour of this oscillatory sequence is obtained by a saddle-point analysis involving two conjugate saddle points. Technical details of the analysis are dealt with by appealing to Wyman's class of admissible functions.