allFaces -- returns all faces of a simplicial complex, up to a given dimension

i1 : R = QQ[a..e];

i2 : S = simplicialComplex {a*b*c*d*e};

i3 : allFaces S

o3 = {a, b, c, d, e, a*b, a*c, a*d, a*e, b*c, b*d, b*e, c*d, c*e, d*e, a*b*c,
     ------------------------------------------------------------------------
     a*b*d, a*b*e, a*c*d, a*c*e, a*d*e, b*c*d, b*c*e, b*d*e, c*d*e, a*b*c*d,
     ------------------------------------------------------------------------
     a*b*c*e, a*b*d*e, a*c*d*e, b*c*d*e, a*b*c*d*e}

o3 : List

i4 : allFaces(2, S)

o4 = {a, b, c, d, e, a*b, a*c, a*d, a*e, b*c, b*d, b*e, c*d, c*e, d*e, a*b*c,
     ------------------------------------------------------------------------
     a*b*d, a*b*e, a*c*d, a*c*e, a*d*e, b*c*d, b*c*e, b*d*e, c*d*e}

o4 : List