English
For fsymm : NonlinearRightInverse f, bound' yields ‖fsymm y‖ ≤ fsymm.nnnorm · ‖y‖ for all y.
Русский
Для fsymm: NonlinearRightInverse f выполняется неравенство ‖fsymm y‖ ≤ fsymm.nnnorm · ‖y‖ для всех y.
LaTeX
$$$$\\|\\text{fsymm}(y)\\| \\leq \\text{fsymm.nnnorm} \\cdot \\|y\\|.$$$$
Lean4
/-- Given a continuous linear equivalence, the inverse is in particular an instance of
`ContinuousLinearMap.NonlinearRightInverse` (which turns out to be linear). -/
noncomputable def toNonlinearRightInverse [RingHomInvPair σ' σ] (f : E ≃SL[σ] F) :
ContinuousLinearMap.NonlinearRightInverse (f : E →SL[σ] F)
where
toFun := f.invFun
nnnorm := ‖(f.symm : F →SL[σ'] E)‖₊
bound' _ := ContinuousLinearMap.le_opNorm (f.symm : F →SL[σ'] E) _
right_inv' := f.apply_symm_apply