theorem Th35: :: NDIFF13:34
for S, E, F, G being RealNormSpace
for Z being Subset of S
for B being Lipschitzian BilinearOperator of E,F,G
for W being PartFunc of S,G
for w being PartFunc of S,[:E,F:]
for u being PartFunc of S,E
for v being PartFunc of S,F st u is_differentiable_on Z & v is_differentiable_on Z & W = B * w & w = <:u,v:> holds
( W is_differentiable_on Z & ( for x being Point of S st x in Z holds
for ds being Point of S holds ((W `| Z) /. x) . ds = (B . ((((u `| Z) /. x) . ds),(v /. x))) + (B . ((u /. x),(((v `| Z) /. x) . ds))) ) )