English
Given a VectorBundleCore with IsContMDiff, the coordinate change maps between two trivializations are C^n on their base intersection.
Русский
Переход координат гладок.
LaTeX
$$$$\\text{ContMDiffOn }\\big( Z.coordChange \\big)\\; (Z.baseSet i \\cap Z.baseSet j) $$$$
Lean4
theorem contMDiffOn (e : Trivialization F (π F E)) [MemTrivializationAtlas e] :
ContMDiffOn (IB.prod 𝓘(𝕜, F)) (IB.prod 𝓘(𝕜, F)) n e e.source :=
by
have : ContMDiffOn (IB.prod 𝓘(𝕜, F)) (IB.prod 𝓘(𝕜, F)) n id e.source := contMDiffOn_id
rw [e.contMDiffOn_iff (mapsTo_id _)] at this
exact (this.1.prodMk this.2).congr fun x hx ↦ (e.mk_proj_snd hx).symm