isFaceOf -- Substitute a face to a different ring.

i1 : K=QQ;

i2 : R=K[x_1..x_5];

i3 : C=simplicialComplex monomialIdeal (x_1*x_2,x_3*x_4*x_5)

o3 = | x_2x_4x_5 x_1x_4x_5 x_2x_3x_5 x_1x_3x_5 x_2x_3x_4 x_1x_3x_4 |

o3 : SimplicialComplex

i4 : F1=face {x_1,x_2}

o4 = x  x  
      1  2

o4 : face with 2 vertices in R

i5 : F2=face {x_1,x_3}

o5 = x  x  
      1  3

o5 : face with 2 vertices in R

i6 : isFaceOf(F1,C)

o6 = false

i7 : isFaceOf(F2,C)

o7 = true