Open torsion statements over K(σ) in positive characteristic (Geyer–Jarden program)
Determine whether the following hold when K is an infinite field of positive characteristic: (a) for e = 1, for almost all σ ∈ G_K, and for any abelian variety A of positive dimension over K(σ), the torsion subgroup A(K(σ))tor is infinite and A(K(σ))[ℓ] ≠ 0 for infinitely many primes ℓ; (b) for e ≥ 2, for almost all σ ∈ G_K^e and any abelian variety A over K(σ), the torsion subgroup A(K(σ))tor is finite.
References
Geyer-Jarden [GJ78] conjectured that Statements (a)-(c) in (3) in this theorem hold for any finitely generated field K over its prime field. We note that the paper of Jacobson-Jarden [JJ84] involves a proof of Statement (a) for K with positive characteristic, but it contains an error as indicated in [JJ85]. Statements (a) and (b) for K which is infinite and has positive characteristic remain open.