We introduce a new method for showing that the roots of the characteristic polynomial of a finite lattice are all nonnegative integers. Our main theorem gives two simple conditions under which the characteristic polynomial factors in this way. We will see that Stanley’s Supersolvability Theorem is a corollary of this result. We can also use this method to demonstrate the factorization of a poly...

We present characteristic-free resolutions and splitting homotopies for the Weyl modules associated to skew-hook shapes. Résumé. Nous présentons des résolutions en caractéristique-libre, et des homotopies associées aux formes du type “skew-hook”.