flips -- legal bistellar flips of a triangulation, computed via topcom

• Usage:

  flips T

• Inputs:
  • T, an instance of the type Triangulation,
• Optional inputs:
  • RegularOnly => a Boolean value, default value true, restrict to flips between regular triangulations (default true)
• Outputs:
  • a list, of circuit pairs $\{neg, pos\}$, one per legal bistellar flip of $T$

i1 : A = transpose matrix {{0,3},{0,1},{-1,-1},{1,-1},{-4,-2},{4,-2}}

o1 = | 0 0 -1 1  -4 4  |
     | 3 1 -1 -1 -2 -2 |

              2       6
o1 : Matrix ZZ  <-- ZZ

i2 : T = regularFineTriangulation A

o2 = triangulation {{0, 1, 2}, {0, 1, 3}, {0, 2, 4}, {0, 3, 5}, {1, 2, 3}, {2, 3, 4}, {3, 4, 5}}

o2 : Triangulation

i3 : flips T

o3 = {{{0, 2, 3}, {1}}, {{1, 4}, {0, 2}}, {{1, 5}, {0, 3}}, {{2, 5}, {3, 4}}}

o3 : List