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Macaulay2 web site
Posets
::
principalFilter
principalFilter -- computes the elements above a given element in a poset
Synopsis
Usage:
F = principalFilter(P, a)
Inputs:
P
,
an object of class
Poset
a
,
a
thing
, an element of the poset
Outputs:
F
,
a
list
, containing all elements greater than or equal to the given element
Description
The filter of a given element of a poset is all the elements in the poset which are greater than or equal to the element.
i1 : P = booleanLattice 3;
i2 : principalFilter(P, "101") o2 = {101, 111} o2 : List
See also
filter
-- computes the elements above given elements in a poset
orderIdeal
-- computes the elements below given elements in a poset
principalOrderIdeal
-- computes the elements below a given element in a poset
Ways to use
principalFilter
:
principalFilter(Poset,Thing)