let S, T be RealNormSpace; for i being Nat ex H being RealNormSpace st
( H = (diff_SP (S,T)) . i & (diff_SP (S,T)) . (i + 1) = R_NormSpace_of_BoundedLinearOperators (S,H) )
let i be Nat; ex H being RealNormSpace st
( H = (diff_SP (S,T)) . i & (diff_SP (S,T)) . (i + 1) = R_NormSpace_of_BoundedLinearOperators (S,H) )
take H = modetrans ((diff_SP (S,T)) . i); ( H = (diff_SP (S,T)) . i & (diff_SP (S,T)) . (i + 1) = R_NormSpace_of_BoundedLinearOperators (S,H) )
thus
H = (diff_SP (S,T)) . i
by Def1, Th8; (diff_SP (S,T)) . (i + 1) = R_NormSpace_of_BoundedLinearOperators (S,H)
thus
(diff_SP (S,T)) . (i + 1) = R_NormSpace_of_BoundedLinearOperators (S,H)
by Def2; verum