Specialization t = 11/9 of a generic rank-4 Mordell family obtained from the Burkhardt quartic, with rational parametrization parameters (u,v,w) = (5,4,-2).
Found by varying the Burkhardt parameters using the rational parametrization of Bruin–Nasserden, followed by a sixth-power-residue Mestre–Nagao sieve, 3-isogeny deduplication, and conductor-aware candidate selection.
PARI/GP 2.17.4 establishes exact rank 11, with bounds [11,11] and 11 independent rational points.
jesper-petersen ·