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Referring to [KR05](@cite) for definitions and technical details, we discuss homogenization and dehomogenization in the context of $\mathbb Z^m$-gradings.
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Referring to [KR05](@cite) for definitions and technical details, we discuss homogenization and dehomogenization in the context of $\mathbb Z^m$-gradings.
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```@docs
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homogenizer(P::MPolyRing{T}, h::VarName; pos::Int=1+ngens(P)) where T
Copy file name to clipboardExpand all lines: docs/src/Groups/action.md
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@@ -69,13 +69,26 @@ orbit(G::PermGroup, omega)
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orbits(Omega::T) where T <: GSetByElements{TG} where TG <: GAPGroup
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is_transitive(Omega::GSet)
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transitivity(Omega::GSet)
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rank_action(Omega::GSet)
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is_primitive(Omega::GSet)
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is_regular(Omega::GSet)
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is_semiregular(Omega::GSet)
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```
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## Block systems of a G-set
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If we have a G-set $\Omega$, a *block system* of $\Omega$ is a partition that is invariant under the action of the associated group.
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The group action on $\Omega$ induces a natural action on such a partition.
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When calling these methods with a `GSet` as the argument, we require that the group action is transitive.
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The blocks are returned as Julia `Set` objects.
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Note that this is in contrast to the return type when calling the methods with a `PermGroup` as the argument, in which case the blocks are sorted vectors of integers.
Copy file name to clipboardExpand all lines: experimental/FTheoryTools/src/AbstractFTheoryModels/attributes.jl
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@req k >=0"Chern class index must be non-negative"
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@req k <=dim(ambient_space(m)) -1"Chern class index must not exceed dimension of the space"
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#Check if we can compute the Chern classes for the toric ambient space
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if check
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@reqis_smooth(ambient_space(m)) &&is_complete(ambient_space(m)) "The Chern classes of the tangent bundle of the toric ambient space are only supported if the toric ambient space is smooth and complete"
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end
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#CAREFUL: The code below works ONLY for hypersurfaces in toric spaces.
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# CAREFUL: It represents the Chern classes of the hypersurface by - so I believe canonical - counterparts in the toric ambient space.
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# CAREFUL: Those counterparts must be restricted to the hypersurface to truly represent the Chern class in question.
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# CAREFUL: Currently, we only integrate those Chern classes against the hypersurface, which automatically executes the restriction in question.
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# If thus far, no non-trivial Chern classes have been computed for this toric variety, add an "empty" vector
# Check if we can compute the Chern classes for the toric ambient space
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if check
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@reqis_smooth(ambient_space(m)) &&is_complete(ambient_space(m)) "The Chern classes of the tangent bundle of the toric ambient space are only supported if the toric ambient space is smooth and complete"
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