MethodError with Semi-algebraic set described by polynomial equalities

[jolouvet]

It seems there is an issue with problems involving measures whose support is a semi-algebraic set described by polynomial equalities.

As an example:

gmp = GMPModel(Mosek.Optimizer)

@polyvar x[1:3]
@variable gmp mu Meas(x[1:3], support=@set(x'*x== 1))
@objective gmp Max Mom(1, mu)

optimize!(gmp)

returns

MethodError: no method matching map_exponents(::typeof(+), ::SumOfSquares.GramMatrix{VariableRef, MonomialBasis{Monomial{DynamicPolynomials.Commutative{DynamicPolynomials.CreationOrder}, Graded{LexOrder}}, MonomialVector{DynamicPolynomials.Commutative{DynamicPolynomials.CreationOrder}, Graded{LexOrder}}}, AffExpr, SymMatrix{VariableRef}}, ::Monomial{DynamicPolynomials.Commutative{DynamicPolynomials.CreationOrder}, Graded{LexOrder}})

It works fine for polynomial inequalities:

@variable gmp mu Meas(x[1:3], support=@set(x'*x<= 1))