Potent preservers of incidence algebras

Jorge J. Garcés, Mykola Khrypchenko

Let $X$ be a finite connected poset, $F$ a field and $I(X,F)$ the incidence algebra of $X$ over $F$. We describe the bijective linear idempotent preservers $\phi :I(X,F)\to I(X,F)$. Na…