Identification and tautology: identity in the works of Husserl and Wittgenstein

A question common to the sixth Logical Research of Husserl and to Wittgenstein's Tractatus is the question of the status of mathematical equations, and more broadly of judgements of identity. It is that of whether the mathematician expresses propositions, which as such bear a character of possible truth, or, on the contrary, simple rules of substitution useful for calculations. As formulated by Frege, this question can be summarized as follows: does mathematical knowledge exist? In reply to this question Husserl's position may be interpreted as being midway between that of Kant and that of Wittgenstein.