Hirzebruch functional equations and complex Krichever genera

Abstract

It is well known that the two-parametric Todd genus and elliptic functions of level $d$ define $n$-multiplicative Hirzebruch genera, if $d$ divides $n+1$. Both these cases are particular cases of Krichever genera defined by the Baker--Akhiezer functions. In this work the inverse problem is solved. Namely, it is proved that only these families of functions define $n$-multiplicative Hirzebruch genera among all the Krichever genera for all $n$.