Let F be a global function field of characteristic p>0, K/F an l-adic Lie extension unramified outside a finite set of places S and A/F an abelian variety. We study Sel_A(K)_l^\vee (the Pontrjagin dual of the Selmer group) and (under some mild hypotheses) prove that it is a finitely generated Z_l[[Gal(K/F)]]-module via generalizations of Mazur's Control Theorem. If Gal(K/F) has no elements of order l and contains a closed normal subgroup H such that Gal(K/F)/H \simeq Z_l, we are able to give sufficient conditions for Sel_A(K)_l^\vee to be finitely generated as Z_l[[H]]-module and, consequently, a torsion Z_l[[\Gal(K/F)]]-module. We deal with both cases l \neq p and l=p.
Control theorems for l-adic Lie extensions of global function fields / Bandini, Andrea; Maria, Valentino. - In: ANNALI DELLA SCUOLA NORMALE SUPERIORE DI PISA. CLASSE DI SCIENZE. - ISSN 0391-173X. - XIV:4(2015), pp. 1065-1092. [10.2422/2036-2145.201304_001]
Control theorems for l-adic Lie extensions of global function fields
BANDINI, Andrea;
2015-01-01
Abstract
Let F be a global function field of characteristic p>0, K/F an l-adic Lie extension unramified outside a finite set of places S and A/F an abelian variety. We study Sel_A(K)_l^\vee (the Pontrjagin dual of the Selmer group) and (under some mild hypotheses) prove that it is a finitely generated Z_l[[Gal(K/F)]]-module via generalizations of Mazur's Control Theorem. If Gal(K/F) has no elements of order l and contains a closed normal subgroup H such that Gal(K/F)/H \simeq Z_l, we are able to give sufficient conditions for Sel_A(K)_l^\vee to be finitely generated as Z_l[[H]]-module and, consequently, a torsion Z_l[[\Gal(K/F)]]-module. We deal with both cases l \neq p and l=p.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.