Space of modular forms of level 80, weight 2, and trivial character

• Label: 80.2.a
• Level: $80$
• Weight: $2$
• Character orbit: 80.a
• Rep. character: $\chi_{80}(1,\cdot)$
• Character field: $\Q$
• Dimension: $2$
• Newform subspaces: $2$
• Sturm bound: $24$
• Trace bound: $3$

Defining parameters

Level:	\( N \)	\(=\)	\( 80 = 2^{4} \cdot 5 \)
Weight:	\( k \)	\(=\)	\( 2 \)
Character orbit:	\([\chi]\)	\(=\)	80.a (trivial)
Character field:			\(\Q\)
Newform subspaces:			\( 2 \)
Sturm bound:			\(24\)
Trace bound:			\(3\)
Distinguishing \(T_p\):			\(3\)

Dimensions

The following table gives the dimensions of various subspaces of \(M_{2}(\Gamma_0(80))\).

	Total	New	Old
Modular forms	18	2	16
Cusp forms	7	2	5
Eisenstein series	11	0	11

The following table gives the dimensions of the cuspidal new subspaces with specified eigenvalues for the Atkin-Lehner operators and the Fricke involution.

\(2\)	\(5\)	Fricke		Total				Cusp				Eisenstein
				All	New	Old		All	New	Old		All	New	Old
\(+\)	\(+\)	\(+\)		\(3\)	\(0\)	\(3\)		\(1\)	\(0\)	\(1\)		\(2\)	\(0\)	\(2\)
\(+\)	\(-\)	\(-\)		\(5\)	\(1\)	\(4\)		\(2\)	\(1\)	\(1\)		\(3\)	\(0\)	\(3\)
\(-\)	\(+\)	\(-\)		\(6\)	\(1\)	\(5\)		\(3\)	\(1\)	\(2\)		\(3\)	\(0\)	\(3\)
\(-\)	\(-\)	\(+\)		\(4\)	\(0\)	\(4\)		\(1\)	\(0\)	\(1\)		\(3\)	\(0\)	\(3\)
Plus space		\(+\)		\(7\)	\(0\)	\(7\)		\(2\)	\(0\)	\(2\)		\(5\)	\(0\)	\(5\)
Minus space		\(-\)		\(11\)	\(2\)	\(9\)		\(5\)	\(2\)	\(3\)		\(6\)	\(0\)	\(6\)

Trace form

2 * q + 2 * q^3 + 2 * q^7 - 2 * q^9 - 4 * q^11 - 2 * q^15 - 4 * q^17 - 4 * q^21 - 10 * q^23 + 2 * q^25 - 4 * q^27 + 4 * q^29 + 12 * q^31 + 6 * q^35 + 8 * q^37 + 4 * q^39 + 18 * q^43 - 4 * q^45 + 2 * q^47 + 6 * q^49 - 12 * q^51 - 4 * q^55 + 8 * q^57 - 8 * q^59 - 14 * q^63 - 4 * q^65 - 10 * q^67 - 12 * q^69 + 12 * q^71 - 4 * q^73 + 2 * q^75 - 16 * q^77 - 8 * q^79 - 2 * q^81 + 10 * q^83 + 8 * q^85 + 12 * q^87 - 12 * q^89 - 12 * q^91 + 8 * q^93 - 8 * q^95 - 12 * q^97 + 12 * q^99

Decomposition of \(S_{2}^{\mathrm{new}}(\Gamma_0(80))\) into newform subspaces

Label	Level	Weight	Char	Prim	Char order	Dim	Rel. Dim	$A$	Field	CM	Self-dual	Twist minimal	Largest	Maximal	Minimal twist	Inner twists	Rank*	Traces					A-L signs		Fricke sign	Coefficient ring index	Sato-Tate	$q$-expansion
																		$a_{2}$	$a_{3}$	$a_{5}$	$a_{7}$		2	5
80.2.a.a	$80$	$2$	80.a	1.a	$1$	$1$	$1$	$0.639$	\(\Q\)	None	✓		✓	✓	40.2.a.a	$1$	$0$	\(0\)	\(0\)	\(1\)	\(4\)		$+$	$-$	$-$	$1$	$\mathrm{SU}(2)$	\(q+q^{5}+4q^{7}-3q^{9}-4q^{11}-2q^{13}+\cdots\)
80.2.a.b	$80$	$2$	80.a	1.a	$1$	$1$	$1$	$0.639$	\(\Q\)	None	✓		✓	✓	20.2.a.a	$1$	$0$	\(0\)	\(2\)	\(-1\)	\(-2\)		$-$	$+$	$-$	$1$	$\mathrm{SU}(2)$	\(q+2q^{3}-q^{5}-2q^{7}+q^{9}+2q^{13}+\cdots\)

Decomposition of \(S_{2}^{\mathrm{old}}(\Gamma_0(80))\) into lower level spaces

\( S_{2}^{\mathrm{old}}(\Gamma_0(80)) \simeq \) \(S_{2}^{\mathrm{new}}(\Gamma_0(20))\)\(^{\oplus 3}\)\(\oplus\)\(S_{2}^{\mathrm{new}}(\Gamma_0(40))\)\(^{\oplus 2}\)