Hadamard products of rational formal power series
The Hadamard product of two rational formal series in one variable over an arbitrary field is again a rational formal series. If we take more than one variable, the result remains valid provided the characteristic of the field of coefficients is different from zero. Using a two variable version of the Newton-Puiseux theorem, the authors prove the above result for the two variables case when the characteristic is zero. The result is not true in case there are three or more variables and the characteristic is zero.
scientific article; zbMATH DE number 4152546
scientific article