English
The derivative mfderiv I I' e x is surjective for x in the source.
Русский
Производная mfderiv I I' e x сюръектна по отношению к касательному пространству.
LaTeX
$$$\text{mfderiv\_surjective}(I,I',e,x)$$$
Lean4
theorem trans (he' : e'.MDifferentiable I' I'') : (e.trans e').MDifferentiable I I'' :=
by
constructor
· intro x hx
simp only [mfld_simps] at hx
exact ((he'.mdifferentiableAt hx.2).comp _ (he.mdifferentiableAt hx.1)).mdifferentiableWithinAt
· intro x hx
simp only [mfld_simps] at hx
exact ((he.symm.mdifferentiableAt hx.2).comp _ (he'.symm.mdifferentiableAt hx.1)).mdifferentiableWithinAt