Challenge: rational points on the order-thirteen curve #
The compiled Tate-normal-form reduction sends a point of exact order thirteen to a rational point on this sextic with abscissa different from zero and negative one. Thus this statement is exactly the missing rational-point classification needed by that branch.
theorem
MazurTheorem.Challenge.xOneThirteen_no_noncuspidal_point
(x y : ℚ)
(hx0 : x ≠ 0)
(hxnegOne : x ≠ -1)
(hcurve : y ^ 2 = MazurTorsion.Kubert.orderThirteenHyperellipticPolynomial x)
:
The explicit X₁(13) sextic has no rational point away from its two
rational affine cusp abscissas.