theorem Th34: :: NDIFF13:33
for S, E, F, G being RealNormSpace
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
for x being Point of S st u is_differentiable_in x & v is_differentiable_in x & x in dom w & W = B * w & w = <:u,v:> holds
( W is_differentiable_in x & w is_differentiable_in x & diff (W,x) = (diff (B,[(u /. x),(v /. x)])) * (diff (w,x)) & diff (w,x) = <:(diff (u,x)),(diff (v,x)):> & ( for ds being Point of S holds (diff (W,x)) . ds = (B . (((diff (u,x)) . ds),(v /. x))) + (B . ((u /. x),((diff (v,x)) . ds))) ) )