flagPoset -- computes the subposet of specified ranks of a ranked poset

Usage:

F = flagPoset(P, L)
Inputs:
- P, an instance of the type Poset,
- L, a list, containing rank indices
Outputs:
- F, an instance of the type Poset, the subposet of $P$ of only the ranks specified in $L$

Description

The flag poset with respect to a list of rank indices is the subposet induced by the specified ranks. The maximal chains of the flag poset can be computed with the flagChains method.

i1 : P = booleanLattice 4;

i2 : rankFunction P

o2 = {0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4}

o2 : List

i3 : flagPoset(P, {2,3})

o3 = Relation Matrix: | 1 0 0 1 0 0 1 0 0 0 |
                      | 0 1 0 1 0 0 0 0 1 0 |
                      | 0 0 1 1 0 0 0 0 0 1 |
                      | 0 0 0 1 0 0 0 0 0 0 |
                      | 0 0 0 0 1 0 1 0 1 0 |
                      | 0 0 0 0 0 1 1 0 0 1 |
                      | 0 0 0 0 0 0 1 0 0 0 |
                      | 0 0 0 0 0 0 0 1 1 1 |
                      | 0 0 0 0 0 0 0 0 1 0 |
                      | 0 0 0 0 0 0 0 0 0 1 |

o3 : Poset

i4 : flagPoset(P, {1})

o4 = Relation Matrix: | 1 0 0 0 |
                      | 0 1 0 0 |
                      | 0 0 1 0 |
                      | 0 0 0 1 |

o4 : Poset

Ways to use flagPoset:

flagPoset(Poset,List)

For the programmer

The object flagPoset is a method function.

The source of this document is in /build/macaulay2-88fgJW/macaulay2-1.25.11+ds/M2/Macaulay2/packages/Posets.m2:2698:0.

flagPoset -- computes the subposet of specified ranks of a ranked poset

Description

See also

Ways to use flagPoset:

For the programmer