idealFromCharacter -- Generate a lattice ideal from a character.

i1 : R = QQ[x,y]

o1 = R

o1 : PolynomialRing

i2 : I = ideal(x^3-1,y-x)

             3
o2 = ideal (x  - 1, - x + y)

o2 : Ideal of R

i3 : cv = isCellular (I,ReturnCellVars=>true)

o3 = {x, y}

o3 : List

i4 : pc = partialCharacter (I,CellVariables=>cv)

o4 = PartialCharacter{c => {1, 1}  }
                      J => {x, y}
                      L => | 1  0 |
                           | -1 3 |

o4 : PartialCharacter

i5 : idealFromCharacter (R,pc) == I

o5 = true