OAI/RingTheory/DirectFiniteness/RibbonSplitting.lean
8 declarations, 0 contain sorry, 0 declared as axioms
- def
OAI.KaplanskyCounterexample.Planar.Ribbon.swapBlackline 15 - lemma
OAI.KaplanskyCounterexample.Planar.Ribbon.swapBlack_twiceline 19 - lemma
OAI.KaplanskyCounterexample.Planar.Ribbon.swapBlack_faceline 25 - lemma
OAI.KaplanskyCounterexample.Planar.Ribbon.swapBlack_components_mergeline 30 - lemma
OAI.KaplanskyCounterexample.Planar.Ribbon.not_blackCycle_of_not_componentline 53 - lemma
OAI.KaplanskyCounterexample.Planar.Ribbon.not_white_faceCycle_of_not_componentline 57 - lemma
OAI.KaplanskyCounterexample.Planar.Ribbon.genusZero_swapBlack_mergeline 65Source documentation
Gluing black vertices from distinct connected components preserves genus zero.
lemma Ribbon.genusZero_swapBlack_merge (R : Ribbon α) (hR : R.GenusZero) (a b : α) (hab : ¬ R.components.r a b) : (R.swapBlack a b).GenusZero := by …Mentions: OAI.KaplanskyCounterexample.Planar.Ribbon, OAI.KaplanskyCounterexample.Planar.Ribbon.GenusZero
- lemma
OAI.KaplanskyCounterexample.Planar.Ribbon.genusZero_swapBlack_splitline 82Source documentation
Splitting one black vertex preserves genus zero, even when the split separates its connected component into two.
lemma Ribbon.genusZero_swapBlack_split (R : Ribbon α) (hR : R.GenusZero) (a b : α) (hne : a ≠ b) (hab : R.black.SameCycle a b) : (R.swapBlack a b).GenusZero := by …Mentions: OAI.KaplanskyCounterexample.Planar.Ribbon, OAI.KaplanskyCounterexample.Planar.Ribbon.GenusZero