Spaces of modular forms generated by eta-quotients

This website provides scripts and log files related to the paper "Spaces of modular forms generated by eta-quotients" written by Jeremy Rouse and John J. Webb. The table below gives a listing of the files, file types, and short descriptions.

Filename File type Description
etamake0.txt Magma script This script takes as input a weight k and a level N and uses LattE, a program for enumerating lattice points in polytopes, to count the number of eta-quotients in Mk0(N)). The LattE executable count must be in the same directory in which magma is run for this script to work. This script is only effective when the level N is fairly small, but high weights k are feasible.
etamake-lattice.txt Magma script This script takes as input a weight k and a level N and enumerates short vectors in the lattice of weakly holomorphic eta-quotients of level N to find all the eta-quotients in Mk0(N)). It does not rely on LattE, and it is most effective when the weight is reasonably small and the level N does not have too many divisors.
etamake9.txt Magma script This script takes as input a range of levels N and tries to prove that the graded ring of modular forms is generated by holomorphic eta-quotients of level N. It attempts to find enough eta-quotients to span M20(N)). To do this it uses a combination of the short vectors method, and a random walk in the lattice of weakly holomorphic eta-quotients to search for holomorphic eta-quotients in M20(N)). If this random walk is not successful, the program reverts to the method used in etamake-lattice.txt. This script is effective for levels with lots of small divisors. (Note: This script was written before the authors realized then whenever N is composite and Γ0(N), the graded ring of modular forms is generated in weight 2. Hence, it includes a check that products of weight 2 eta-quotients that were found span the weight 4 and weight 6 spaces.)
etamake9.out Magma list This list is output by etamake9.txt. It gives a list of the levels N with 1 ≤ N ≤ 524 for which Γ0(N) has no elliptic points. For each level, it indicates whether M20(N)) is spanned by eta-quotients, whether the graded ring of level N modular forms is generated by eta-quotients, the dimension of M20(N)), the dimension of the subspace spanned by eta-quotients, and a lower bound for the number of eta-quotients in M20(N)). (This lower bound is sharp if the space is not
etamake9.data Text file This file lists output of the script etamake9.txt. For those levels N for which M20(N)) is spanned by eta-quotients, it lists eta-quotients that span the space.
etamake10.txt Magma script This script attempts to prove that every modular form in Mk0(N)) is expressible as a linear combination of weakly holomorphic eta-quotients. To do this, it tries to find eta-quotients that span Mr+20(N)), where r is the weight of the form EN,N, the level N eta-quotient with all of its zeroes at the cusp at infinity. It uses a similar method to etamake9.txt.