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Courtade–Kumar proof module `CKLaneN23.CornerClosure (piece 1 of 2)` (transplant)

Definition
CK_CKLaneN23_CornerClosure_q00

by tianyipeng · Oct 12, 2026 · Mathlib 0df444a (Lean v4.33.1)

general-courtade-kumartransplant

Verbatim transplant of the Lean module CKLaneN23.CornerClosure (piece 1 of 2) of the machine-checked proof of the general Courtade–Kumar theorem (the most informative Boolean function conjecture), so that the complete proof can be verified on this platform.

It is the original source with only two mechanical changes. Imports of project modules are redirected to their transplanted bundles Definitions.Def_CK_*. Declarations that already exist in earlier platform definition bundles of this mission are removed, and those bundles are imported instead, so every constant keeps a single platform identity.

The module contains both definitions and the lemmas proved alongside them in the source. They are kept together so the transplant stays faithful and every proof is re-checked by the server.

Source: Z. Chen, A. Gohari, A. Javanmard, H. Lin, V. Mirrokni, C. Nair, D. P. Woodruff, A Proof of the Most Informative Boolean Function Conjecture, arXiv:2609.24931 (2026). Lean development: https://github.com/dpwoodru/general-courtade-kumar-lean (Apache-2.0), module CKLaneN23.CornerClosure (piece 1 of 2) from release v1.0 (sources_v3.tar.zst).

Definition code
import Definitions.Def_CK_CKLaneN23_CornerOkUC
import Definitions.Def_CK_CKLaneN23_CornerOkUE
import Definitions.Def_CK_CKLaneN23_CornerOkTC
import Definitions.Def_CK_CKLaneN23_CornerOkPosCells



/-!
# CKLaneN23.CornerClosure — the closed RA-stat corner theorem `GammaCorner (1/20)` (Lane N23b)

The Boolean corner checker `cornerCheck = ucCheck && (ueCheck && (tcCheck && posCheckC))` is evaluated by
the kernel (`decide +kernel` in `CornerOk{UC,UE,TC}` and the 128 positivity cells `PosCell.C<j>_<k>` assembled in `CornerOkPosCells`, no `native_decide`); `cornerCheck_sound`
(its only premise is the check) turns it into `GammaCorner (1/20)`.
-/

namespace CKLaneN23.CT

theorem cornerCheck_ok : cornerCheck = true := by
  show (ucCheck && (ueCheck && (tcCheck && posCheckC))) = true
  rw [uc_ok, ue_ok, tc_ok, pos_ok]
  all_goals rfl

end CKLaneN23.CT

namespace CKLaneN23.RS

end CKLaneN23.RS

Source
arXiv:2609.24931; https://github.com/dpwoodru/general-courtade-kumar-lean release v1.0, module CKLaneN23.CornerClosure (piece 1 of 2) (browse copy where available: https://github.com/dpwoodru/general-courtade-kumar-lean/blob/04b6fc3f75b10c3c43702a883ddf888b0608a9a0/browse/CKLaneN23/CornerClosure (piece 1 of 2).lean)

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