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Description
Describe the bug
When comparing polynomials from different rings I get inconsistent behaviour. Sometimes I just get false and sometimes an error.
To Reproduce
julia> R0,(x0) = polynomial_ring(QQ,1)
(Multivariate polynomial ring in 1 variable over QQ, QQMPolyRingElem[x1])
julia> R1,(x1) = polynomial_ring(ZZ,1)
(Multivariate polynomial ring in 1 variable over ZZ, ZZMPolyRingElem[x1])
julia> R2,(x2) = polynomial_ring(GF(2),1)
(Multivariate polynomial ring in 1 variable over GF(2), FqMPolyRingElem[x1])
julia> x0 == x1
false
julia> x0 == x2
false
julia> R3,(x3) = polynomial_ring(GF(3),1)
(Multivariate polynomial ring in 1 variable over GF(3), FqMPolyRingElem[x1])
julia> x2 == x3
ERROR: parents do not match
Stacktrace:
[1] error(s::String)
@ Base ./error.jl:35
[2] check_parent
@ ~/.julia/packages/AbstractAlgebra/QjFtH/src/AbstractAlgebra.jl:208 [inlined]
[3] check_parent
@ ~/.julia/packages/AbstractAlgebra/QjFtH/src/AbstractAlgebra.jl:207 [inlined]
[4] ==(a::FqMPolyRingElem, b::FqMPolyRingElem)
@ Nemo ~/.julia/packages/Nemo/4P3uO/src/flint/fq_default_mpoly.jl:295
[5] ==(A::Vector{FqMPolyRingElem}, B::Vector{FqMPolyRingElem})
@ Base ./abstractarray.jl:2943
[6] top-level scope
@ REPL[18]:1
julia> x0 == x3
false
Expected behavior
We have many places where we first compare the "surrounding space" before comparing the actual objects. So I would expect an error to get thrown. E.g. try
cube(2) == cube(3)
Additional context
Maybe this needs a styleguide entry, I actually did not look it up.