Indivisibility of class numbers of real quadratic function fields

In this paper we work on indivisibility of the class numbers of real quadratic function fields. We find an explicit expression for a lower bound of the density of real quadratic function fields (with constant field F) whose class numbers are not divisible by a given prime ℓ. We point out that the explicit lower bound of such a density we found only depends on the prime ℓ, the degrees of the discriminants of real quadratic function fields, and the condition: either |F|≡1(modℓ) or not.