I was reading this post on why polynomials can't have negative exponenents.
The most voted answer seems to bring out a difference between some objects called "Lambert Polynomials" and Laurent Polynomials.
These "Lambert polynomials" are cited as a counterexample to rational functions becasue they miss the property of being closed under division.
As reported in the original post "This property doesn't hold for your 'Lambert polynomials', because there's no finite expression in positive and/or negative powers of x that corresponds to the function $\displaystyle \frac{1}{1+x}$."
Then the author conludes explaining the notion of a Laurent Polynomial.
I didn't get the difference between the two notions as they were laid out in that post, but I'm very interested in the topic.
I hope someone can clarify the difference for me.