-- -*- M2-comint -*- hash: 11095793514555780799

i1 : R = QQ[x_1..x_7];

i2 : G = complementGraph cycle R; --odd antihole with 7 vertices

i3 : isPerfect G

o3 = false

i4 : H = cycle(R,4)

o4 = Graph{"edges" => {{x , x }, {x , x }, {x , x }, {x , x }}}
                         1   2     2   3     3   4     1   4
           "ring" => R
           "vertices" => {x , x , x , x , x , x , x }
                           1   2   3   4   5   6   7

o4 : Graph

i5 : isPerfect H

o5 = true

i6 : 
