Moscow-Petersburg seminar on low-dimensional mathematics April 4, 2003, 16:00, room 311 of PDMI M.M.Vinogradov (Moscow) Algebraic differential calculus over modules and dioles. One of the remarkable mathematical discoveries of the last century is finding out the algebraic nature of differential calculus and developing a theory of linear differential operators over arbitrary commutative algebras. We present here a brief outline of this theory and formulate an algebraic formalism describing the so-called Der-operators, that is, vector fields on fiber bundles that cover vector fields on the base manifold. In order to do this, a concept of diole is introduced, and differential calculus over diole categories is built. --------------------------- http://www.pdmi.ras.ru/~lowdimma