principalFilter -- computes the elements above a given element in a poset

• Usage:

  F = principalFilter(P, a)

• Inputs:
  • P, an instance of the type Poset,
  • a, a thing, an element of the poset
• Outputs:
  • F, a list, containing all elements greater than or equal to the given element

i1 : P = booleanLattice 3;

i2 : principalFilter(P, "101")

o2 = {101, 111}

o2 : List