theorem Th66: :: NDIFF13:65
for F, G being non trivial RealBanachSpace ex I being PartFunc of (R_NormSpace_of_BoundedLinearOperators (F,G)),(R_NormSpace_of_BoundedLinearOperators (G,F)) st
( dom I = InvertibleOperators (F,G) & rng I = InvertibleOperators (G,F) & I is one-to-one & I is_continuous_on InvertibleOperators (F,G) & ex J being PartFunc of (R_NormSpace_of_BoundedLinearOperators (G,F)),(R_NormSpace_of_BoundedLinearOperators (F,G)) st
( J = I " & J is one-to-one & dom J = InvertibleOperators (G,F) & rng J = InvertibleOperators (F,G) & J is_continuous_on InvertibleOperators (G,F) ) & ( for u being Point of (R_NormSpace_of_BoundedLinearOperators (F,G)) st u in InvertibleOperators (F,G) holds
I . u = Inv u ) & ( for n being Nat holds
( I is_differentiable_on n + 1, InvertibleOperators (F,G) & diff (I,(n + 1),(InvertibleOperators (F,G))) is_continuous_on InvertibleOperators (F,G) ) ) )