A combinatorial proof of the Kronecker--Weber Theorem in positive characteristic

Abstract

In this paper we present a combinatorial proof of the Kronecker--Weber Theorem for global fields of positive characteristic. The main tools are the use of Witt vectors and their arithmetic developed by H. L. Schmid. The key result is to obtain, using counting arguments, how many $p$--cyclic extensions exist of fixed degree and bounded conductor where only one prime ramifies are there. We then compare this number with the number of subextensions of cyclotomic function fields of the same type and verify that these two numbers are the same.