let S be RealNormSpace-Sequence; for T being RealNormSpace
for Z being Subset of (product S)
for G being non empty FinSequence of dom S
for s being Element of dom S
for f being PartFunc of (product S),T holds
( Partdiff_SP (S,(Partdiff_SP (S,T,G,(len G))),<*s*>,1) = Partdiff_SP (S,T,(G ^ <*s*>),((len G) + 1)) & (f `partial| (Z,G)) `partial| (Z,s) = PartDiffSeq (f,Z,(G ^ <*s*>),((len G) + 1)) )
let T be RealNormSpace; for Z being Subset of (product S)
for G being non empty FinSequence of dom S
for s being Element of dom S
for f being PartFunc of (product S),T holds
( Partdiff_SP (S,(Partdiff_SP (S,T,G,(len G))),<*s*>,1) = Partdiff_SP (S,T,(G ^ <*s*>),((len G) + 1)) & (f `partial| (Z,G)) `partial| (Z,s) = PartDiffSeq (f,Z,(G ^ <*s*>),((len G) + 1)) )
let Z be Subset of (product S); for G being non empty FinSequence of dom S
for s being Element of dom S
for f being PartFunc of (product S),T holds
( Partdiff_SP (S,(Partdiff_SP (S,T,G,(len G))),<*s*>,1) = Partdiff_SP (S,T,(G ^ <*s*>),((len G) + 1)) & (f `partial| (Z,G)) `partial| (Z,s) = PartDiffSeq (f,Z,(G ^ <*s*>),((len G) + 1)) )
let G be non empty FinSequence of dom S; for s being Element of dom S
for f being PartFunc of (product S),T holds
( Partdiff_SP (S,(Partdiff_SP (S,T,G,(len G))),<*s*>,1) = Partdiff_SP (S,T,(G ^ <*s*>),((len G) + 1)) & (f `partial| (Z,G)) `partial| (Z,s) = PartDiffSeq (f,Z,(G ^ <*s*>),((len G) + 1)) )
let s be Element of dom S; for f being PartFunc of (product S),T holds
( Partdiff_SP (S,(Partdiff_SP (S,T,G,(len G))),<*s*>,1) = Partdiff_SP (S,T,(G ^ <*s*>),((len G) + 1)) & (f `partial| (Z,G)) `partial| (Z,s) = PartDiffSeq (f,Z,(G ^ <*s*>),((len G) + 1)) )
let f be PartFunc of (product S),T; ( Partdiff_SP (S,(Partdiff_SP (S,T,G,(len G))),<*s*>,1) = Partdiff_SP (S,T,(G ^ <*s*>),((len G) + 1)) & (f `partial| (Z,G)) `partial| (Z,s) = PartDiffSeq (f,Z,(G ^ <*s*>),((len G) + 1)) )
set I = <*s*>;
A1:
len <*s*> = 1
by FINSEQ_1:39;
hence
Partdiff_SP (S,(Partdiff_SP (S,T,G,(len G))),<*s*>,1) = Partdiff_SP (S,T,(G ^ <*s*>),((len G) + 1))
by Th17; (f `partial| (Z,G)) `partial| (Z,s) = PartDiffSeq (f,Z,(G ^ <*s*>),((len G) + 1))
PartDiffSeq ((f `partial| (Z,G)),Z,<*s*>,(len <*s*>)) =
(f `partial| (Z,G)) `partial| (Z,(<*s*> . 1))
by A1, Th13
.=
(f `partial| (Z,G)) `partial| (Z,s)
;
hence
(f `partial| (Z,G)) `partial| (Z,s) = PartDiffSeq (f,Z,(G ^ <*s*>),((len G) + 1))
by A1, Th17; verum