A general formula is obtained for the number of points lying on a plane algebraic curve over the finite local ring \(\mathrm{GF}(q)[t]/(t^n)\) (\(n > 1\)) whose equation has coefficients in \(\mathrm{GF}(q)\) and under the restriction that it has only simple and ordinary singular points.
Citation
Dirk Keppens, Wim Mielants. On the Number of Points on a Plane Algebraic Curve over \(GF(q)[t]/t^n\)[J], Ars Combinatoria, Volume 040. 121-128. .