Newforms
Hecke characteristic polynomials
The eigenvalue of T=T5โ+3T11โ generates each orbit's coefficient field; on the newspace its characteristic polynomial factors over Q as one irreducible factor per orbit:
Dimensions
| Newforms S2newโ(ฮ0โ(756)) | 8 |
|---|
| Old forms | 119 |
| Cusp forms S2โ(ฮ0โ(756)) | 127 |
|---|
| Eisenstein series E2โ(ฮ0โ(756)) | 35 |
| Modular forms M2โ(ฮ0โ(756)) | 162 |
|---|
Decomposition of the old subspace
S2oldโ(ฮ0โ(756))= S2newโ(ฮ0โ(14))โ8 โ S2newโ(ฮ0โ(21))โ9 โ S2newโ(ฮ0โ(27))โ6 โ S2newโ(ฮ0โ(36))โ4 โ S2newโ(ฮ0โ(42))โ6 โ S2newโ(ฮ0โ(54))โ4 โ S2newโ(ฮ0โ(63))โ6 โ S2newโ(ฮ0โ(84))โ3 โ S2newโ(ฮ0โ(108))โ2 โ S2newโ(ฮ0โ(126))โ4 โ S2newโ(ฮ0โ(189))โ3 โ S2newโ(ฮ0โ(252))โ2 โ S2newโ(ฮ0โ(378))โ2
Provenance
Stored in the atlas: computed by Sagebrush's modular symbols engine in 0.507 s (one thread) and proven: the dimensions are certified, and the characteristic polynomial of T over Z is reconstructed by CRT past a rigorous coefficient bound.
The engine's checks
dim M^+ at levels [1, 2, 3, 4, 6, 7, 9, 12, 14, 18, 21, 27, 28, 36, 42, 54, 63, 84, 108, 126, 189, 252, 378, 756]: [0, 1, 1, 2, 3, 1, 2, 5, 4, 5, 4, 4, 7, 9, 12, 11, 10, 22, 21, 28, 26, 54, 76, 150] (certified at ell = 2147483647)T = [(5, 1), (11, 3)]; h of degree 8 = 1 x 8 (phi(ord eps) x dim S_k^new); 2 primes, 0 rejected
Recompute it yourself
In Sage mode at sagebrush.space (or npx sagebrush --sage):
newform_orbits(756, 2)
With the Rust engine (source), in engine/:
cargo run --release -p sagebrush-web --example atlas -- 756:2 1000
โ 755.2.a ยท 757.2.a โ