> > "Every one of these graphs has a unique chromatic polynomial" > This is incorrect. Two different graphs may have the same chromatic polynomial. For exampl

> > "Every one of these graphs has a unique chromatic polynomial" > This is incorrect. Two different graphs may have the same chromatic polynomial. For example, all trees of N vertices have the same chromatic polynomial: x(x-1)^(N-1) As soverytired (https://news.ycombinator.com/item?id=14697626 https://news.ycombinator.com/item?id=14697626) points out, you're refuting the claim that the graphs have distinct chromatic polynomials. To say that a graph has a unique chromatic polynomial means that it has only one, not that no other graph has the same one. (For example, (almost?) everyone has a unique biological mother.)