A note on towers of function fields over finite fields

Abstract

For a tower F 1 ⊆ F 2 ⊆ ⋯ of algebraic function fields F i/F q, define τ := lim i→∞ N(F i)/g(F i), where N(F i) is the number of rational places and g(F i) is the genus of F i/F q. The purpose of this note is to calculate A for a class of towers which was studied in [1], [2] and [3].