Unclear Documentation on Creating SOS Polynomials

[mohammedehab2002]

The documentation says creating SOS polynomials is the same as creating free polynomials but replacing Poly(basis) with SOSPoly(basis), but that doesn't seem to be true. The constraint seems to create a GramMatrix rather than a polynomial, and while the documentation claims a polynomial p is set to x'Qx, I can't find how to access that polynomial.
I tried manually creating the polynomial as x'Qx, but in my case, I need x to be a Chebyshev basis. I tried using the MultivariateBases package for that, but I get an error saying ChebyshevBasisFirstKind doesn't support adjoint.

[blegat]

The GramMatrix is a polynomial in the form s = b' * Q * b where b is some polynomial basis. If you want to convert it to a polynomial, you can do polynomial(s). About Chebyshev basis, the support is being improved in #355 but it's till a work in progress.