Certain values of Gaussian hypergeometric series and a family of algebraic curves (1208.0495v1)

Abstract: Let $\lambda \in \mathbb{Q}\setminus {0, -1}$ and $l \geq 2$. Denote by $C_{l,\lambda}$ the nonsingular projective algebraic curve over $\mathbb{Q}$ with affine equation given by $$y^l=(x-1)(x^2+\lambda).$$ In this paper we give a relation between the number of points on $C_{l, \lambda}$ over a finite field and Gaussian hypergeometric series. We also give an alternate proof of a result of McCarthy (2010). We find some special values of ${{3}}F_2$ and ${{2}}F_1$ Gaussian hypergeometric series. Finally we evaluate the value of ${_{3}}F_2(4)$ which extends a result of Ono (1998).