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replace custom GroupRing constructor by alternating_emb function

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This commit is contained in:
kalmarek 2018-08-15 19:17:37 +02:00
parent 854ddb42a1
commit 6047d496d5
1 changed files with 3 additions and 4 deletions
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7
src/Projections.jl
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@ -79,11 +79,10 @@ function central_projection(RG::GroupRing, chi::AbstractCharacter, T::Type=Ratio
return result
end
function (RG::GroupRing{Gr,T})(V::Vector{T}, S::Type=Rational{Int}; alt=false) where {Gr<:Generic.PermGroup, T<:GroupElem}
function alternating_emb(RG::GroupRing{Gr,T}, V::Vector{T}, S::Type=Rational{Int}) where {Gr<:Generic.PermGroup, T<:GroupElem}
res = RG(S)
for g in V
c = (alt ? sign(g)*one(S) : one(S))
res[g] += c/length(V)
res[g] += sign(g)
end
return res
end
@ -112,7 +111,7 @@ function idempotents(RG::GroupRing{Generic.PermGroup{S}}, T::Type=Rational{Int})
idems = Vector{GroupRingElem{T}}()
for p in projs
append!(idems, [RG(p, T), RG(p, T, alt=true)])
append!(idems, [RG(p, T)//length(p), alternating_emb(RG, p, T)//length(p)])
end
return unique(idems)