Defining parameters
| Level: | \( N \) | \(=\) | \( 81 = 3^{4} \) |
| Weight: | \( k \) | \(=\) | \( 2 \) |
| Character orbit: | \([\chi]\) | \(=\) | 81.a (trivial) |
| Character field: | \(\Q\) | ||
| Newform subspaces: | \( 1 \) | ||
| Sturm bound: | \(18\) | ||
| Trace bound: | \(0\) |
Dimensions
The following table gives the dimensions of various subspaces of \(M_{2}(\Gamma_0(81))\).
| Total | New | Old | |
|---|---|---|---|
| Modular forms | 15 | 6 | 9 |
| Cusp forms | 4 | 2 | 2 |
| Eisenstein series | 11 | 4 | 7 |
The following table gives the dimensions of the cuspidal new subspaces with specified eigenvalues for the Atkin-Lehner operators and the Fricke involution.
| \(3\) | Total | Cusp | Eisenstein | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| All | New | Old | All | New | Old | All | New | Old | ||||
| \(+\) | \(6\) | \(2\) | \(4\) | \(1\) | \(0\) | \(1\) | \(5\) | \(2\) | \(3\) | |||
| \(-\) | \(9\) | \(4\) | \(5\) | \(3\) | \(2\) | \(1\) | \(6\) | \(2\) | \(4\) | |||
Trace form
Decomposition of \(S_{2}^{\mathrm{new}}(\Gamma_0(81))\) into newform subspaces
| Label | Dim | $A$ | Field | CM | Traces | A-L signs | $q$-expansion | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| $a_{2}$ | $a_{3}$ | $a_{5}$ | $a_{7}$ | 3 | |||||||
| 81.2.a.a | $2$ | $0.647$ | \(\Q(\sqrt{3}) \) | None | \(0\) | \(0\) | \(0\) | \(4\) | $-$ | \(q+\beta q^{2}+q^{4}-\beta q^{5}+2q^{7}-\beta q^{8}+\cdots\) | |
Decomposition of \(S_{2}^{\mathrm{old}}(\Gamma_0(81))\) into lower level spaces
\( S_{2}^{\mathrm{old}}(\Gamma_0(81)) \simeq \) \(S_{2}^{\mathrm{new}}(\Gamma_0(27))\)\(^{\oplus 2}\)