Atlas › Modular forms › Weight 12 › Level 16 › 16.12.a

Newspace 16.12.a: $S_{12}^{\mathrm{new}}(\Gamma_0(16))$

Newforms

Label	Dim	Coefficient field	Trace form
16.12.a.a	1	$\mathbb{Q}$	$q - 252q^{3} + 4830q^{5} + 16744q^{7} + O(q^{8})$
16.12.a.b	1	$\mathbb{Q}$	$q + 36q^{3} - 3490q^{5} + 55464q^{7} + O(q^{8})$
16.12.a.c	1	$\mathbb{Q}$	$q + 516q^{3} - 10530q^{5} - 49304q^{7} + O(q^{8})$
16.12.a.d	2	$\mathbb{Q}(\sqrt{109})$	$2q - 56q^{3} + 7868q^{5} - 91056q^{7} + O(q^{8})$

Hecke characteristic polynomials

The eigenvalue of $T = T_{3} + T_{5}$ generates each orbit's coefficient field; on the newspace its characteristic polynomial factors over $\mathbb{Q}$ as one irreducible factor per orbit:

Orbit	Characteristic polynomial of $T$
16.12.a.a	$x - 4578$
16.12.a.b	$x + 3454$
16.12.a.c	$x + 10014$
16.12.a.d	$x^{2} - 7812x - 60195580$

Dimensions

Newforms $S_{12}^{\mathrm{new}}(\Gamma_0(16))$	5
Old forms	14
Cusp forms $S_{12}(\Gamma_0(16))$	19
Eisenstein series $E_{12}(\Gamma_0(16))$	6
Modular forms $M_{12}(\Gamma_0(16))$	25

Decomposition of the old subspace

$S_{12}^{\mathrm{old}}(\Gamma_0(16)) =$ $S_{12}^{\mathrm{new}}(\Gamma_0(1))^{\oplus 5}$ $\oplus$ $S_{12}^{\mathrm{new}}(\Gamma_0(4))^{\oplus 3}$ $\oplus$ $S_{12}^{\mathrm{new}}(\Gamma_0(8))^{\oplus 2}$

Provenance

Stored in the atlas: computed by Sagebrush's modular symbols engine in 0.342 s (one thread) and proven: the dimensions are certified, and the characteristic polynomial of $T$ over $\mathbb{Z}$ is reconstructed by CRT past a rigorous coefficient bound.

The engine's checks

dim M^+ at levels [1, 2, 4, 8, 16]: [2, 4, 7, 13, 24] (certified at ell = 2147483629)
T = [(3, 1), (5, 1)]; h of degree 5 = 1 x 5 (phi(ord eps) x dim S_k^new); 3 primes, 0 rejected

Open in the notebook · JSON · stored data

Recompute it yourself

In Sage mode at sagebrush.space (or npx sagebrush --sage):

newform_orbits(16, 12)

With the Rust engine (source), in engine/:

cargo run --release -p sagebrush-web --example atlas -- 16:12 1000

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