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PhylogeneticTrees :: joinIdeal

joinIdeal -- compute the join of several ideals



This function computes the ideal of the join by constructing the abstract join and then projecting with elimination.

Setting the optional argument DegreeLimit to \{d\} will produce only the generators of the join ideal up to degree d.

This method is general and will work for arbitrary polynomial ideals, not just phylogenetic ideals.

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

o1 = R

o1 : PolynomialRing
i2 : I = ideal {a-d,b^2-c*d}

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)

o4 = ideal(b  - a*c)

o4 : Ideal of R

See also

Ways to use joinIdeal :

For the programmer

The object joinIdeal is a method function with options.