symbolicPowerJoin -- computes the symbolic power of the prime ideal using join of ideals.

Synopsis

Computes the $n$-th symbolic power of the prime ideal $P$, using join of ideals.

This is the algorithm in Seth Sullivant's "Combinatorial symbolic powers", J. Algebra 319 (2008), no. 1, 115-142.

i1 : A = QQ[x,y,z];

i2 : symbolicPowerJoin(ideal(x,y),2)

             2        2
o2 = ideal (y , x*y, x )

o2 : Ideal of A