dual(MonomialIdeal,List) -- the Alexander dual

Synopsis

Usage:
dual(I,e)
Function: dual
Inputs:
- I, a monomial ideal, a monomial ideal
- e, a list, a list of exponents
Outputs:
- the Alexander dual of I formed with respect to the monomial whose exponents are listed in e

The monomial corresponding to e should be divisible by all of the minimal generators of I.