Moreover, by considering all possible pairs (*N*, *deg*), we
obtain a natural subring *T*(*l*) of modular forms with
respect to Gamma_1(*l*). We construct an explicit set of
generators for *T*(*l*), and show that *T*(*l*) is
stable under the action of the Hecke operators. Finally, we relate
*T*(*l*) to the Hirzebruch elliptic genera that are modular
with respect to Gamma_1(*l*).

- p2.eps (5480 bytes)
- toric.dvi (114108 bytes) [1999 Nov 8]
- toric.dvi.gz (44372 bytes)
- toric.ps (367268 bytes)
- toric.ps.gz (138580 bytes)

Lev A. Borisov and Paul E. Gunnells <gunnells@math.columbia.edu>