Fregean solution of the paradox of analysis and the criterion of difference of thoughts

At the beginning of this essay a formulation of the paradox of analysis is presented. Standard Fregean solution of this paradox is then displayed, as well as the problems that this solution faces. After words, another solution of the paradox of analysis is shown, which can be found in Frege's late writings. It will be demonstrated that this solution, at least at first sight, is incompatible with the criterion of difference of thoughts that is standardly attributed to Frege. In the end, a possible solution to this incompatibility is suggested.