Invariants
| Base field: | $\F_{31}$ |
| Dimension: | $2$ |
| L-polynomial: | $1 - 4 x + 26 x^{2} - 124 x^{3} + 961 x^{4}$ |
| Frobenius angles: | $\pm0.231221817116$, $\pm0.626957092346$ |
| Angle rank: | $2$ (numerical) |
| Number field: | 4.0.256000.4 |
| Galois group: | $C_4$ |
| Jacobians: | $70$ |
This isogeny class is simple and geometrically simple, primitive, ordinary, and not supersingular. It is principally polarizable and contains a Jacobian.
Newton polygon
This isogeny class is ordinary.
| $p$-rank: | $2$ |
| Slopes: | $[0, 0, 1, 1]$ |
Point counts
Point counts of the abelian variety
| $r$ | $1$ | $2$ | $3$ | $4$ | $5$ |
|---|---|---|---|---|---|
| $A(\F_{q^r})$ | $860$ | $959760$ | $883805660$ | $854662440960$ | $820178001537500$ |
| $r$ | $1$ | $2$ | $3$ | $4$ | $5$ | $6$ | $7$ | $8$ | $9$ | $10$ |
|---|---|---|---|---|---|---|---|---|---|---|
| $C(\F_{q^r})$ | $28$ | $998$ | $29668$ | $925438$ | $28648348$ | $887480678$ | $27512379748$ | $852891237118$ | $26439607752988$ | $819628217204198$ |
Jacobians and polarizations
This isogeny class is principally polarizable and contains the Jacobians of 70 curves (of which all are hyperelliptic):
- $y^2=18 x^6+29 x^5+24 x^4+30 x^3+18 x^2+20 x+19$
- $y^2=23 x^6+26 x^5+28 x^4+6 x^3+28 x^2+23 x+22$
- $y^2=30 x^6+3 x^5+2 x^4+22 x^3+2 x^2+5 x+26$
- $y^2=11 x^6+25 x^5+27 x^4+7 x^3+24 x^2+29 x+2$
- $y^2=27 x^6+9 x^5+13 x^4+16 x^3+10 x^2+8 x+23$
- $y^2=5 x^6+27 x^5+12 x^4+12 x^3+11 x^2+2 x+30$
- $y^2=27 x^6+3 x^5+5 x^4+23 x^3+15 x^2+20 x+22$
- $y^2=10 x^6+30 x^5+26 x^4+8 x^3+20 x^2+5 x+8$
- $y^2=14 x^6+18 x^5+15 x^4+6 x^3+29 x^2+19 x+15$
- $y^2=30 x^6+4 x^5+12 x^4+14 x^3+24 x^2+23 x+11$
- $y^2=6 x^6+29 x^5+8 x^4+26 x^3+26 x^2+14 x+8$
- $y^2=10 x^6+x^5+30 x^4+18 x^3+24 x^2+12 x+25$
- $y^2=15 x^6+24 x^5+13 x^4+12 x^3+25 x^2+7 x$
- $y^2=11 x^6+12 x^5+25 x^4+22 x^3+11 x^2+10 x+19$
- $y^2=17 x^6+23 x^5+20 x^4+29 x^3+30 x^2+7 x+2$
- $y^2=29 x^6+14 x^5+27 x^4+19 x^3+27 x^2+24 x+14$
- $y^2=19 x^6+13 x^5+24 x^4+11 x^3+26 x^2+20 x+28$
- $y^2=25 x^6+18 x^5+13 x^4+17 x^3+23 x^2+10 x+7$
- $y^2=29 x^6+6 x^4+2 x^3+3 x^2+13 x+15$
- $y^2=15 x^6+7 x^5+20 x^4+30 x^3+7 x^2+9 x+26$
- and 50 more
Decomposition and endomorphism algebra
All geometric endomorphisms are defined over $\F_{31}$.
Endomorphism algebra over $\F_{31}$| The endomorphism algebra of this simple isogeny class is 4.0.256000.4. |
Base change
This is a primitive isogeny class.
Twists
Below is a list of all twists of this isogeny class.
| Twist | Extension degree | Common base change |
|---|---|---|
| 2.31.e_ba | $2$ | (not in LMFDB) |