Defining parameters
Level: | \( N \) | = | \( 18 = 2 \cdot 3^{2} \) |
Weight: | \( k \) | = | \( 4 \) |
Nonzero newspaces: | \( 2 \) | ||
Newform subspaces: | \( 3 \) | ||
Sturm bound: | \(72\) | ||
Trace bound: | \(1\) |
Dimensions
The following table gives the dimensions of various subspaces of \(M_{4}(\Gamma_1(18))\).
Total | New | Old | |
---|---|---|---|
Modular forms | 35 | 7 | 28 |
Cusp forms | 19 | 7 | 12 |
Eisenstein series | 16 | 0 | 16 |
Trace form
Decomposition of \(S_{4}^{\mathrm{new}}(\Gamma_1(18))\)
We only show spaces with even parity, since no modular forms exist when this condition is not satisfied. Within each space \( S_k^{\mathrm{new}}(N, \chi) \) we list available newforms together with their dimension.
Label | \(\chi\) | Newforms | Dimension | \(\chi\) degree |
---|---|---|---|---|
18.4.a | \(\chi_{18}(1, \cdot)\) | 18.4.a.a | 1 | 1 |
18.4.c | \(\chi_{18}(7, \cdot)\) | 18.4.c.a | 2 | 2 |
18.4.c.b | 4 |
Decomposition of \(S_{4}^{\mathrm{old}}(\Gamma_1(18))\) into lower level spaces
\( S_{4}^{\mathrm{old}}(\Gamma_1(18)) \cong \) \(S_{4}^{\mathrm{new}}(\Gamma_1(1))\)\(^{\oplus 6}\)\(\oplus\)\(S_{4}^{\mathrm{new}}(\Gamma_1(2))\)\(^{\oplus 3}\)\(\oplus\)\(S_{4}^{\mathrm{new}}(\Gamma_1(3))\)\(^{\oplus 4}\)\(\oplus\)\(S_{4}^{\mathrm{new}}(\Gamma_1(6))\)\(^{\oplus 2}\)\(\oplus\)\(S_{4}^{\mathrm{new}}(\Gamma_1(9))\)\(^{\oplus 2}\)\(\oplus\)\(S_{4}^{\mathrm{new}}(\Gamma_1(18))\)\(^{\oplus 1}\)