isSubface -- Test whether a face is a subface of another face.

• Usage:

  isSubface(F,G)

• Inputs:
  • F, an instance of the type Face,
  • G, an instance of the type Face,
• Outputs:
  • a Boolean value,

i1 : K=QQ;

i2 : R=K[x_0..x_4];

i3 : G=face {x_0,x_1,x_2}

o3 = x  x  x  
      0  1  2

o3 : face with 3 vertices in R

i4 : F1=face {x_0,x_2}

o4 = x  x  
      0  2

o4 : face with 2 vertices in R

i5 : F2=face {x_0,x_3}

o5 = x  x  
      0  3

o5 : face with 2 vertices in R

i6 : isSubface(F1,G)

o6 = true

i7 : isSubface(F2,G)

o7 = false