theorem Th60: :: NDIFF13:59
for i being Nat
for S, E, F being RealNormSpace
for u being PartFunc of S,E
for v being PartFunc of S,F
for w being PartFunc of S,[:E,F:]
for Z being Subset of S st w = <:u,v:> & u is_differentiable_on i + 1,Z & v is_differentiable_on i + 1,Z holds
( w is_differentiable_on i + 1,Z & ex T being Lipschitzian LinearOperator of [:(diff_SP ((i + 1),S,E)),(diff_SP ((i + 1),S,F)):],(diff_SP ((i + 1),S,[:E,F:])) st diff (w,(i + 1),Z) = T * <:(diff (u,(i + 1),Z)),(diff (v,(i + 1),Z)):> )