Fordham
    University
Equations of Riemann surfaces with automorphisms

Genus 4, \( \delta = 0\)

CheckGenus4.txt
Locus Group ID Signature Generators Comments and Favorite Equations Additional files
1 (120,34)=\(S_5\) (2,4,5)
\( (-x_0,-x_1,-x_2,-x_2+x_3) \)
\( (x_0+x_1,-x_0-x_2,-x_0-x_3,-x_3) \)
Bring's curve. General trigonal
\( x_0^2 + x_0 x_1 + x_1^2 - x_1x_2+ x_2^2 - x_2 x_3 + x_3^2 \)
\( x_0^2 x_1 + x_0 x_1^2 + x_1^2 x_2 - x_1x_2^2+ x_2^2 x_3 - x_2x_3^2 \)
Genus-4-120-34.htm
2 (72,42) (2,3,12) \(\left[ \begin{array}{rrrr} -1 & 0 & 0 & 0 \\ 0 & 0 & 0 & -i \\ 0 & 0 & -1 & 0 \\ 0 & i & 0 & 0 \end{array} \right] , \qquad \left[ \begin{array}{rrrr} -\zeta_6 & 0 & 0 & 0 \\ 0 & -\frac{1}{2}\zeta_{12} & \frac{1}{2}\zeta_{3}& \frac{1}{2}\zeta_{12} \\ 0 & \zeta_{12} & 0 & \zeta_{12} \\ 0 & -\frac{1}{2}\zeta_{12}& -\frac{1}{2}\zeta_{3} & \frac{1}{2}\zeta_{12} \end{array} \right]\)
Cyclic trigonal \(y^3 = x(x^4-1)\)
Canonical ideal: \(x_1x_3-x_2^2 \)
\(x_0^3 - x_1^2 x_2 +x_2 x_3^2 \)
Genus-4-72-42.htm
3 (72,40) (2,4,6)
\((-x_0,x_2,x_1,-x_3)\)
\( (-x_2,\zeta_6^2x_0,\zeta_6x_3,x_1)\)
Cyclic trigonal \( y^3 = (x^3-1)^2(x^3+1)\)
Canonical ideal: \(x_0 x_3-x_1 x_2,\)
\( x_1^3-x_0^3-x_3^3-x_2^3\)
Genus-4-72-40.htm
4 (40,8) (2,4,10)
\( (1, 14)(2, 12)(3, 9)(4, 7)(5, 17)(8, 20)(11, 18)(13, 16)(15, 19)\)
\( (1, 5, 3, 2)(4, 11, 7, 15)(6, 8, 10, 13)(9, 18, 14, 19)(12, 16, 17, 20)\)
Hyperelliptic \(y^2 = x^{10}-1\) Genus-4-40-8.txt
5 (36,12) (2,6,6)
\((-x_0,\zeta_3 x_3,-x_2,-\zeta_6 x_1) \)
\((\zeta_3 x_0,-\zeta_3 x_3, \zeta_6 x_2, -x_1) \)
Cyclic trigonal \( y^3 = (x^3-1)(x^3+1)\)
Canonical ideal: \( x_1 x_3-x_2^2,\)
\( x_0^3-x_3^3+x_1^3\)
Genus-4-36-12.htm
6 (32,19) (2,4,16)
\( (1, 4)(2, 14)(3, 12)(5, 11)(6, 8)(7, 9)(13, 15)\)
\( (1, 13, 5, 8)(2, 4, 9, 11)(3, 7, 12, 14)(6, 10, 15, 16)\)
Hyperelliptic \( y^2 = x^9-x\) Genus-4-32-19.txt
7 (24,3) (3,4,6)
\( (2, 3, 5)(6, 8, 7) \)
\((1, 8, 4, 3)(2, 7, 6, 5) \)
Hyperelliptic \( y^2 = x(x^4-1)(x^4+2i\sqrt{3}+1) \)Genus-4-24-3.txt
8 \( (18,2) = Z_{18} \) (2,9,18)
\( (1, 2)(3, 7)(4, 8)(5, 9)(6, 10)(11, 15)(12, 16)(13, 17)(14, 18) \)
\( (1, 3, 11, 4, 12, 14, 6, 13, 5)(2, 7, 15, 8, 16, 18, 10, 17, 9)\)
Hyperelliptic \(y^2=x^9-1\)Genus-4-18-2.txt
9 \( (15,1) = Z_{15}\) (3,5,15)
\( (\zeta_{3}^{2} x_0,\zeta_{3} x_1, \zeta_{3}x_2, \zeta_{3} x_3)\)
\( (\zeta_{5} x_0,\zeta_{5}^3 x_1,\zeta_{5}^2 x_2,\zeta_{5} x_3)\)
Cyclic trigonal \(y^3 = x^5-1 \)
Canonical ideal: \( x_1 x_3 -x_2^2\)
\( x_0^3 - x_1^2 x_2 +x_3^3 \)
Genus-4-15-1.htm

Genus 4, \( \delta = 1\)

Locus Group ID Signature Generators Comments and Favorite Equations Additional files
10 (36,10) (2,2,2,3)
\( (-x_0,-\zeta_3^2 x_2,-\zeta_3 x_1,-x_3) \)
\((x_3,-x_1,-x_2,x_0) \)
\( (-\zeta_3 x_3, x_2,x_1,-\zeta_3^2 x_0)\)
Cyclic trigonal \( y^3 = (x^3+t)^2(tx^3-1) \)
Canonical ideal: \(x_0x_3-x_1x_2 \)
\( x_1^3+t x_0^3+x_2^3- t x_3^3 \)
Genus-4-36-10.htm
11 (24,12)=\(S_4\) (2,2,2,4)
\( (-x_0,-x_2,-x_1,-x_4)\)
\( (x_2,-x_1,x_0,-x_4)\)
\((-x_0,x_2,x_1,-x_4) \)
General trigonal
\( x_0^2+x_1^2+x_2^2+tx_3^2\)
\( x_0x_1x_2-x_3^3\)
Favorite equations
Algorithm output
12 (20,4) (2,2,2,5)
\((1, 2)(3, 4)(5, 7)(6, 8)(9, 10)\)
\( (1, 3)(2, 4)(5, 6)(7, 8)\)
\((1, 10)(2, 9)(3, 8)(4, 6)(5, 7) \)
Hyperelliptic \( y^2 = (x^5-t^5)(x^5-t^{-5})\) Genus-4-20-4.txt
13 (18,3) (2,2,3,3)
\( (-x_0, x_3,-x_2,x_1) \)
\( (-x_0,\zeta_3x_3,-x_2,\zeta_3^2 x_1,)\)
\( (x_0,\zeta_3^2x_1,\zeta_3,x_2,x_3) \)
Cyclic trigonal \( y^3 = (x^3+t)(tx^3-1)\)
Canonical ideal: \( x_1 x_3 - x_2^2 \)
\( x_0^3-x_3^3+t x_2^3+x_1^3 \)
Genus-4-18-3.htm
14 (16,7) (2,2,2,8)
\( (1, 4)(2, 6)(3, 7)(5, 8) \)
\( (1, 8)(2, 7)(3, 6)(4, 5) \)
\( (1, 7)(3, 4)(5, 8) \)
Hyperelliptic \( y^2 = x(x^4-t^4)(x^4-t^{-4}) \) Genus-4-16-7.txt