nefRayContractions -- produces all contractions corresponding to rays in the nef cone

• Usage:

  nefRayContractions X

• Inputs:
  • X, a normal toric variety,
• Outputs:
  • a list, of ToricMaps obtained by each ray of the nef cone

i1 : X = hirzebruchSurface 1;

i2 : L = nefRayContractions X

o2 = {| 1 0 |, | 1 0 |}
               | 0 1 |

o2 : List

i3 : assert(isProjective target L_0 and dim target L_0 == 1);

i4 : assert(isProjective target L_1 and dim target L_1 == 2);

i5 : assert(rank picardGroup target L_1 == 1);