Proposition 4.2
ProvedLocalConjugacy.proposition_4_2Suppose a profinite group acts transitively and with closed point stabilizers on some nonempty set and that supplements some abelian . If for each prime , a Sylow -subgroup of fixes an element of , then fixes an element of .
import Definitions.Def_LocalConjugacy_Groups /- Proposition 4.2: an arbitrary transitive action on a nonempty set, with closed stabilizers. The abelian normal subgroup need not act transitively. This is an open draft target. The deliberate `sorry` is the target proof hole; all definitions and the structural proofs on which the statement rests compile without admitted proofs. -/ universe u v open LocalConjugacy
theorem LocalConjugacy.proposition_4_2 {G : ProfiniteGrp.{u}} {Ω : Type v} [MulAction G Ω] [Nonempty Ω]
(N H : Subgroup G) [N.Normal] (hN : IsClosed (N : Set G))
(hH : IsClosed (H : Set G)) [IsMulCommutative N]
(hHN : Supplements N H) (htrans : MulAction.IsPretransitive G Ω)
(hclosed : ∀ x : Ω, IsClosed (MulAction.stabilizer G x : Set G))
(hlocal : SylowFixedPoints (Ω := Ω) H) : HasFixedPoint (Ω := Ω) H := by sorryRead-back
What the Lean code literally says, in plain math · GPT-6 family (exact model variant not exposed)
For every profinite group in universe , every nonempty set in universe with a -action, and closed subgroups , suppose that is normal in and has commutative multiplication, and that every element of can be expressed as with . Suppose that the action is transitive, meaning that for every some satisfies , and that each stabilizer is closed in . If for every natural prime there exist a Sylow pro- subgroup of and a point fixed by all elements of , then there exists a point fixed by every element of . A Sylow pro- subgroup of a subgroup means a subgroup that is closed in , for which every quotient by an open normal subgroup of has the property that every element is killed by some power with , and that is maximal under inclusion among the closed subgroups of contained in with this quotient property. The points and subgroups in the hypothesis may vary with . No topology on is specified, and there is no separately assumed continuity of its action beyond the closed-stabilizer condition. Empty is excluded, but singleton , trivial groups, and trivial Sylow subgroups are allowed. All primes are quantified, no finiteness of or is required, and the expression need not be unique.
Confirmed by the mission captain (proposal self-audit).
Confirmed by the moderator at approval.