formal power series

Noun

• Any finite or infinite series of the form $\backslash textstyle\; a\_0\; +\; a\_1\; x\; +\; a\_2\; x^2\; \backslash dots\; =\; \backslash sum\_i\{a\_i\; x^i\}$, where the a_i are numbers, but it is understood that no value is assigned to x.