theorem :: NDIFF_1:23

for S, T being RealNormSpace
for R being PartFunc of S,T st R is total holds
( R is RestFunc-like iff for r being Real st r > 0 holds
ex d being Real st
( d > 0 & ( for z being Point of S st z <> 0. S & ||.z.|| < d holds
(||.z.|| ") * ||.(R /. z).|| < r ) ) )