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32 lines
875 B
Julia
32 lines
875 B
Julia
import AbstractAlgebra
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using GroupsCore
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# disambiguation
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GroupsCore.order(
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::Type{I},
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G::AbstractAlgebra.Generic.SymmetricGroup,
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) where {I<:Integer} = I(factorial(G.n))
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# disambiguation
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GroupsCore.order(
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::Type{I},
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g::AbstractAlgebra.Generic.Perm,
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) where {I<:Integer} =
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I(foldl(lcm, length(c) for c in AbstractAlgebra.cycles(g)))
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# correct the AA length:
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Base.length(G::AbstractAlgebra.Generic.SymmetricGroup) = order(Int, G)
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# genuinely new methods:
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Base.IteratorSize(::Type{<:AbstractAlgebra.AbstractPermutationGroup}) = Base.HasLength()
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function GroupsCore.gens(G::AbstractAlgebra.Generic.SymmetricGroup{I}) where {I}
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a, b = one(G), one(G)
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circshift!(a.d, b.d, -1)
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b.d[1], b.d[2] = 2, 1
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return [a, b]
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end
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Base.deepcopy_internal(g::AbstractAlgebra.Generic.Perm, ::IdDict) =
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AbstractAlgebra.Generic.Perm(deepcopy(g.d), false)
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