Dimension of SOS sets

[odow]

Should we forbid dimension=0 for SOS sets? What does this even mean?

You could argue that throwing an error on MOI.SOS1(Float64[]) is a breaking change, but I don't really set a good reason why anyone would ever want to do it. There's also an argument for making dimension > 1 for SOS1, and dimension > 2 for SOS2...

julia> using JuMP

julia> model = Model();

julia> @constraint(model, VariableRef[] in SOS1())
[] ∈ MathOptInterface.SOS1{Float64}(Float64[])

Discuss...