On the existence of dimension zero divisors in algebraic function fields defined over Fq

الأصل · EN

Let F/Fq be an algebraic function field of genus g defined over a finite field Fq. We obtain new results on the existence, the number and the density of dimension zero divisors of degree g-k in F where k is a positive integer. In particular, for q=2,3 we prove that there always exists a dimension zero divisor of degree γ-1 where γis the q-rank of F. We also give a necessary and sufficient condition for the existence of a dimension zero divisor of degree g-k for a hyperelliptic field F in terms of its Zeta function.