Theorems · Theorem · global analysis

contMDiffWithinAt_iff_le_ne_infty

∀ {𝕜 : Type u_1} [inst : NontriviallyNormedField 𝕜] {E : Type u_2} [inst_1 : NormedAddCommGroup E]
  [inst_2 : NormedSpace 𝕜 E] {H : Type u_3} [inst_3 : TopologicalSpace H] {I : ModelWithCorners 𝕜 E H} {M : Type u_4}
  [inst_4 : TopologicalSpace M] [inst_5 : ChartedSpace H M] {E' : Type u_5} [inst_6 : NormedAddCommGroup E']
  [inst_7 : NormedSpace 𝕜 E'] {H' : Type u_6} [inst_8 : TopologicalSpace H'] {I' : ModelWithCorners 𝕜 E' H'}
  {M' : Type u_7} [inst_9 : TopologicalSpace M'] [inst_10 : ChartedSpace H' M'] {f : M → M'} {s : Set M} {x : M}
  {n : WithTop ℕ∞}, ContMDiffWithinAt I I' n f s x ↔ ∀ m ≤ n, m ≠ ↑⊤ → ContMDiffWithinAt I I' m f s x

A function is C^n within a set at a point iff it is C^m within this set at this point, for any m ≤ n which is different from ∞. This result is useful because, when m ≠ ∞, being C^m extends locally to a neighborhood, giving flexibility for local proofs.

Defined in

Mathlib.Geometry.Manifold.ContMDiff.Defs

Cited by

2 results in Mathlib

Foundations

Depth 180 from the axioms · uses propext, Classical.choice, Quot.sound

Assumes

NontriviallyNormedFieldNormedAddCommGroupNormedSpaceTopologicalSpaceTopologicalSpaceChartedSpaceNormedAddCommGroupNormedSpaceTopologicalSpaceTopologicalSpaceChartedSpace