OAI/Geometry/HyperbolicGroups/WordPictureExist.lean
7 declarations, 0 contain sorry, 0 declared as axioms
- lemma
OAI.HyperbolicObstruction.PictureSwitch.IsBoundary.rotateline 17 - def
OAI.HyperbolicObstruction.WordPictures.WordPicture.rotateline 32 - def
OAI.HyperbolicObstruction.WordPictures.WordPicture.conjugateLetterline 43 - def
OAI.HyperbolicObstruction.WordPictures.WordPicture.conjugateline 53 - def
OAI.HyperbolicObstruction.WordPictures.pictureSubgroupline 64Source documentation
Elements represented by actual finite genus-zero diagrams. The subgroup and its normality are proved by gluing, reflecting and attaching a whisker.
def pictureSubgroup (R : Set (Word A)) : Subgroup (FreeGroup A) where …
- instance
OAI.HyperbolicObstruction.WordPictures.(instance at line 74)line 74 - theorem
OAI.HyperbolicObstruction.WordPictures.picture_existenceline 83Source documentation
Van Kampen realization at the freely represented boundary level: every null element has an actual finite genus-zero side-pairing with only the specified relator faces. The next literal-boundary step is free folding.
theorem picture_existence {R : Set (Word A)} (w : Word A) (h : PresentedGroup.mk (FreeGroup.mk '' R) (FreeGroup.mk w) = 1) : ∃ v, FreeGroup.mk v = FreeGroup.mk w ∧ Nonempty (WordPicture R v) := by …Mentions: OAI.HyperbolicObstruction.WordPictures.Word, OAI.HyperbolicObstruction.WordPictures.WordPicture