isTriangular -- whether a chordal network is triangular

• Usage:

  isTriangular N

• Inputs:
  • N, an instance of the type ChordalNet,
• Outputs:
  • a Boolean value, true if N is triangular, and false otherwise

i1 : R = QQ[a..e,MonomialOrder=>Lex];

i2 : I = ideal {a*b, b*c, c*d, a*e, d*e};

o2 : Ideal of R

i3 : N = chordalNet I;

i4 : isTriangular N

o4 = false

i5 : chordalTria N;

i6 : isTriangular N

o6 = true