### Abstract

Formal Puiseux series are generalisations of formal power
series and formal Laurent series that also allow for fractional
exponents. They have the following general form: \[\sum_{i=N}^\infty
a_{i/d} X^{i/d}\] where *N* is an integer and
*d* is a positive integer.

This entry defines these series including their basic algebraic properties. Furthermore, it proves the Newtonâ€“Puiseux Theorem, namely that the Puiseux series over an algebraically closed field of characteristic 0 are also algebraically closed.