Colored Eulerian Polynomials and the Colored Permutohedron

This paper introduces a colored generalization of the Eulerian polynomials, denoted the $\alpha$-colored Eulerian polynomials. We first compute these polynomials by taking the $h$-vector of the $\alpha$-colored permutohedron, a colored analog of the permutohedron which we develop. We also arrive at the $\alpha$-colored Eulerian polynomials combinatorially by defining a new notion of descent for colored permutations.