joinIdeal -- compute the join of several ideals

• Usage:

  joinIdeal(I,J)

  joinIdeal L

• Inputs:
  • I, an ideal,
  • J, an ideal,
  • L, a list, of ideals in the same ring
• Optional inputs:
  • DegreeLimit => ..., default value {}
• Outputs:
  • an ideal, the join of the input ideals

i1 : R = QQ[a,b,c,d]

o1 = R

o1 : PolynomialRing

i2 : I = ideal {a-d,b^2-c*d}

                    2
o2 = ideal (a - d, b  - c*d)

o2 : Ideal of R

i3 : J = ideal {a,b,c}

o3 = ideal (a, b, c)

o3 : Ideal of R

i4 : joinIdeal(I,J)

            2
o4 = ideal(b  - a*c)

o4 : Ideal of R