  When written in terms of $\vartheta$-functions, the classical
Frobenius-Stickelberger pseudo-addition formula takes a very simple form.
Generalizations of this functional identity are studied, where the functions
involved are derivatives (including derivatives with respect to the modular
parameter) of the elliptic trilogarithm function introduced by Beilinson and
Levin. A differential identity satisfied by this function is also derived.
These generalized Frobenius-Stickelberger identities play a fundamental role in
the development of elliptic solutions of the Witten-Dijkgraaf-Verlinde-Verlinde
equations of associativity, with the simplest case reducing to the above
mentioned differential identity.
