These are notes on approaching Bernoulli polynomials as eigenvalues of certain operators acting on polynomials. It is my re-interpretation of work of E. H. Lehmer. (A new approach to Bernoulli polynomials, Amer. Math. Monthly 95(1988), 905-911.) I wrote this note at the end of my Ph.D. studies around 1989.

These are unpublished notes in Spanish, written in 1985 when I was finishing my undergraduate degree in Buenos Aires, on defining a group law on degenerate cubics. More precisely, on cubics consisting of a smooth conic and a line. Depending on the number of intersection points of the conic and the line over the given ground field (0,1, or 2 points) you get the circle, the additive or the multiplicative group respectively.