OAI/Geometry/SurfaceImmersion/Whitney/RegularSheetDoubleChart.lean
1 declarations, 0 contain sorry, 0 declared as axioms
At a transverse pair of regular points, both projections of a local smooth double-curve chart are regular.
- theorem
OAI.ClosedSurfaceR4.FiniteOrderSmoothing.regular_sheet_double_chartline 15