Pursuing polynomial bounds on torsion

Abstract

We show that for all ϵ > 0, there is a constant C(ϵ) > 0 such that for all elliptic curves E defined over a number field F with j(E) ∈ Q we have $$\# E\left( F \right)\left[ {tors} \right] \leq C\left( \in \right){\left[ {F:\mathbb{Q}} \right]^{5 + 2 + \in }}$$ . We pursue further bounds on the size of the torsion subgroup of an elliptic curve over a number field E/F that are polynomial in [F: Q] under restrictions on j(E). We give an unconditional result for j(E) lying in a fixed quadratic field that is not imaginary of class number one as well as two further results, one conditional on GRH and one conditional on the strong boundedness of isogenies of prime degree for non-CM elliptic curves.