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# momentGraph(GKMVariety,MomentGraph) -- define a moment graph for a GKM variety

- Function: momentGraph
- Usage:
    `momentGraph(X,G)`
- Inputs:
  - X, a GKM variety,
  - G, a moment graph,
- Outputs:

## Description

This methods sets a given MomentGraph G to be the moment graph of a GKMVariety X. If a moment graph was already defined for X, then overwrites it and prints that it has done so.

    i1 : R = makeCharacterRing 4

    o1 = R

    o1 : PolynomialRing

    i2 : X = makeGKMVariety({set{0},set{1},set{2},set{3}},R)

    o2 = a "GKM variety" with an action of a 4-dimensional torus

    o2 : GKMVariety

    i3 : X.?momentGraph

    o3 = false

    i4 : PP3 = projectiveSpace 3

    o4 = a "GKM variety" with an action of a 4-dimensional torus

    o4 : GKMVariety

    i5 : G = momentGraph PP3

    o5 = a "moment graph" on 4 vertices with 6 edges

    o5 : MomentGraph

    i6 : momentGraph(X,G)

    i7 : X.?momentGraph

    o7 = true

    i8 : momentGraph X

    o8 = a "moment graph" on 4 vertices with 6 edges

    o8 : MomentGraph

    i9 : momentGraph(X,G)
     warning: overwriting a previously defined moment graph on this GKM variety

## See also

- momentGraph(GKMVariety) -- view the moment graph of a GKM variety
- momentGraph(List,HashTable,Ring) -- creates a moment graph

## Ways to use this method:

- momentGraph(GKMVariety,MomentGraph) -- define a moment graph for a GKM variety

The source of this document is in /build/macaulay2-88fgJW/macaulay2-1.25.11+ds/M2/Macaulay2/packages/GKMVarieties/Documentation_GKMVarieties.m2:1292:0.