Atlas › Modular forms › Weight 2 › Level 279 › 279.2.a

Newspace 279.2.a: $S_{2}^{\mathrm{new}}(\Gamma_0(279))$

Newforms

Label	Dim	Coefficient field	Trace form	AL signs
279.2.a.a	2	$\mathbb{Q}(\sqrt{5})$	$2q - q^{2} - q^{4} - 2q^{5} - 4q^{7} + O(q^{8})$	−
279.2.a.b	2	$\mathbb{Q}(\sqrt{5})$	$2q + 3q^{2} + 3q^{4} + 4q^{5} - 4q^{7} + O(q^{8})$	+
279.2.a.c	3	degree 3	$3q + 2q^{4} + 2q^{5} + 4q^{7} + O(q^{8})$	+
279.2.a.d	6	degree 6	$6q + 12q^{4} + 8q^{7} + O(q^{8})$	−

Hecke characteristic polynomials

The eigenvalue of $T = T_{2} + T_{5}$ 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 $T$
279.2.a.a	$x^{2} + 3x + 1$
279.2.a.b	$x^{2} - 7x + 11$
279.2.a.c	$x^{3} - 2x^{2} - 4x + 7$
279.2.a.d	$x^{6} - 40x^{4} + 172x^{2} - 75$

Dimensions

Newforms $S_{2}^{\mathrm{new}}(\Gamma_0(279))$	13
Old forms	16
Cusp forms $S_{2}(\Gamma_0(279))$	29
Eisenstein series $E_{2}(\Gamma_0(279))$	7
Modular forms $M_{2}(\Gamma_0(279))$	36

Decomposition of the old subspace

$S_{2}^{\mathrm{old}}(\Gamma_0(279)) =$ $S_{2}^{\mathrm{new}}(\Gamma_0(31))^{\oplus 3}$ $\oplus$ $S_{2}^{\mathrm{new}}(\Gamma_0(93))^{\oplus 2}$

Provenance

Stored in the atlas: computed by Sagebrush's modular symbols engine in 0.186 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, 3, 9, 31, 93, 279]: [0, 1, 2, 3, 12, 34] (certified at ell = 2147482951)
T = [(2, 1), (5, 1)]; h of degree 13 = 1 x 13 (phi(ord eps) x dim S_k^new); 2 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(279, 2)

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

cargo run --release -p sagebrush-web --example atlas -- 279:2 1000

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