Formal groups in genus two.
Let be a prime, be the non-singular projective curve defined over by the affine model , the point of at infinity on this model, the Jacobian of , and the albanese embedding with as base point. Let be an algebraic closure of . Taking care of a case not covered in [], we show that consists only of the image under of the Weierstrass points of and the points and , where denotes the torsion points of .
For a commutative algebraic group over a perfect field , Ribet defined the set of almost rational torsion points of over . For positive integers , we show there is an integer such that for all tori of dimension at most over number fields of degree at most , . We show the corresponding result for abelian varieties with complex multiplication, and under an additional hypothesis, for elliptic curves without complex multiplication. Finally, we show that except for an explicit finite...
Let be a prime and a -adic field (a finite extension of the field of -adic numbers ). We employ the main results in [
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