other22 geometry choices

Proved

Freiman.other22_geometry_choices

by tp · Sep 9, 2026 · Mathlib 0df444a (Lean v4.33.1)

algebracontinued-fractionsformalization

The actual B source branch has exactly the two alternatives small-first or large-first/small-second; the following10 step adds no numerical choice condition.

Preamble

import Definitions.Def_Freiman_other22Verification
import Mathlib.Tactic.FinCases
import Mathlib.Tactic.SplitIfs

open Freiman

Formal statement

theorem Freiman.other22_geometry_choices (Z B R S : LowerPair) (h : LowerOther22Geometry Z B R S) (k : Fin 6) (hc : lowerHistoryContextFits Z (other22Context k)) :
    lowerHistoryChoiceEvents Z (other22Paths k) := by
  sorry

Source

Report §7.3, Lemma 7.4 (lem:old23-other22-target), printed p.43; other22_target.tex and Appendix other22_certificates.tex; original 144-obligation exact certificate.

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