IANAL and I didnt read the DOI paper, but as I think you are mostly right. I think the DOI can require that a solution must be compatible with or have the same

IANAL and I didnt read the DOI paper, but as I think you are mostly right. I think the DOI can require that a solution must be compatible with or have the same features as Microsoft's solution. However, they cannot say the solution MUST be the Microsoft product, and I think that is what Google is arguing.