DegreeLift doesn't work for maps of multigraded rings
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- Macaulay2
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Description
It seems like the DegreeLift option for ring maps between multigraded rings doesn't preserve homogeneity, which I presume is the main point of it.
```m2
A = QQ[x,y, Degrees => {{1,0}, {0,1}}]
B = newRing(A, Degrees => reverse degrees A)
f1 = map(A, B, gens A, DegreeMap => reverse);
isHomogeneous f1 -- true
isHomogeneous inverse f1 -- false
f2 = map(A, B, gens A, DegreeMap => reverse, DegreeLift => reverse);
isHomogeneous f2 -- true
isHomogeneous inverse f2 -- false
```
Related: #2368
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Research direction
Start by reproducing the provided Macaulay2 examples for DegreeLift on maps between multigraded rings, comparing f1 and f2 with their inverses. Trace the DegreeLift handling and verify the fix by confirming that the inverse of the DegreeLift map preserves homogeneity in the shown case.
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