let X be RealUnitarySpace; :: thesis: for x being Point of X
for p being FinSequence of the carrier of X st len p >= 1 holds
for q being FinSequence of REAL st dom p = dom q & ( for i being Nat st i in dom q holds
q . i = the scalar of X . [x,(p . i)] ) holds
x .|. ( the addF of X "**" p) = addreal "**" q

let x be Point of X; :: thesis: for p being FinSequence of the carrier of X st len p >= 1 holds
for q being FinSequence of REAL st dom p = dom q & ( for i being Nat st i in dom q holds
q . i = the scalar of X . [x,(p . i)] ) holds
x .|. ( the addF of X "**" p) = addreal "**" q

let p be FinSequence of the carrier of X; :: thesis: ( len p >= 1 implies for q being FinSequence of REAL st dom p = dom q & ( for i being Nat st i in dom q holds
q . i = the scalar of X . [x,(p . i)] ) holds
x .|. ( the addF of X "**" p) = addreal "**" q )

assume A1: len p >= 1 ; :: thesis: for q being FinSequence of REAL st dom p = dom q & ( for i being Nat st i in dom q holds
q . i = the scalar of X . [x,(p . i)] ) holds
x .|. ( the addF of X "**" p) = addreal "**" q

let q be FinSequence of REAL ; :: thesis: ( dom p = dom q & ( for i being Nat st i in dom q holds
q . i = the scalar of X . [x,(p . i)] ) implies x .|. ( the addF of X "**" p) = addreal "**" q )

assume that
A2: dom p = dom q and
A3: for i being Nat st i in dom q holds
q . i = the scalar of X . [x,(p . i)] ; :: thesis: x .|. ( the addF of X "**" p) = addreal "**" q
consider f being sequence of the carrier of X such that
A4: f . 1 = p . 1 and
A5: for n being Nat st 0 <> n & n < len p holds
f . (n + 1) = the addF of X . ((f . n),(p . (n + 1))) and
A6: the addF of X "**" p = f . (len p) by A1, FINSOP_1:1;
A7: Seg (len q) = dom p by A2, FINSEQ_1:def 3
.= Seg (len p) by FINSEQ_1:def 3 ;
then A8: len q = len p by FINSEQ_1:6;
len q >= 1 by A1, A7, FINSEQ_1:6;
then consider g being sequence of REAL such that
A9: g . 1 = q . 1 and
A10: for n being Nat st 0 <> n & n < len q holds
g . (n + 1) = addreal . ((g . n),(q . (n + 1))) and
A11: addreal "**" q = g . (len q) by FINSOP_1:1;
defpred S1[ Nat] means ( 1 <= $1 & $1 <= len q implies g . $1 = the scalar of X . [x,(f . $1)] );
A12: S1[ 0 ] ;
now :: thesis: for n being Nat st S1[n] & 1 <= n + 1 & n + 1 <= len q holds
g . (n + 1) = the scalar of X . [x,(f . (n + 1))]
let n be Nat; :: thesis: ( S1[n] & 1 <= n + 1 & n + 1 <= len q implies g . (n + 1) = the scalar of X . [x,(f . (n + 1))] )
assume A13: S1[n] ; :: thesis: ( 1 <= n + 1 & n + 1 <= len q implies g . (n + 1) = the scalar of X . [x,(f . (n + 1))] )
now :: thesis: ( 1 <= n + 1 & n + 1 <= len q implies g . (n + 1) = the scalar of X . [x,(f . (n + 1))] )
assume that
A14: 1 <= n + 1 and
A15: n + 1 <= len q ; :: thesis: g . (n + 1) = the scalar of X . [x,(f . (n + 1))]
per cases ( n = 0 or n <> 0 ) ;
suppose A16: n = 0 ; :: thesis: g . (n + 1) = the scalar of X . [x,(f . (n + 1))]
1 in Seg (len p) by A1, FINSEQ_1:1;
then 1 in dom q by A2, FINSEQ_1:def 3;
hence g . (n + 1) = the scalar of X . [x,(f . (n + 1))] by A3, A4, A9, A16; :: thesis: verum
end;
suppose A17: n <> 0 ; :: thesis: g . (n + 1) = the scalar of X . [x,(f . (n + 1))]
then 0 < n ;
then A18: 0 + 1 <= n by INT_1:7;
A19: (n + 1) - 1 < (len q) - 0 by A15, XREAL_1:15;
A20: n + 1 in Seg (len q) by A14, A15, FINSEQ_1:1;
then A21: n + 1 in dom q by FINSEQ_1:def 3;
A22: n + 1 in dom p by A2, A20, FINSEQ_1:def 3;
A23: n in NAT by ORDINAL1:def 12;
dom f = NAT by FUNCT_2:def 1;
then A24: f . n in rng f by FUNCT_1:3, A23;
rng f c= the carrier of X by RELAT_1:def 19;
then reconsider z = f . n as Element of X by A24;
A25: p . (n + 1) in rng p by A22, FUNCT_1:3;
rng p c= the carrier of X by RELAT_1:def 19;
then reconsider y = p . (n + 1) as Element of X by A25;
thus g . (n + 1) = addreal . (( the scalar of X . [x,(f . n)]),(q . (n + 1))) by A10, A13, A18, A19
.= addreal . (( the scalar of X . [x,(f . n)]),( the scalar of X . [x,(p . (n + 1))])) by A3, A21
.= addreal . (( the scalar of X . [x,(f . n)]),(x .|. y)) by BHSP_1:def 1
.= addreal . ((x .|. z),(x .|. y)) by BHSP_1:def 1
.= (x .|. z) + (x .|. y) by BINOP_2:def 9
.= x .|. (z + y) by BHSP_1:2
.= the scalar of X . [x,( the addF of X . ((f . n),(p . (n + 1))))] by BHSP_1:def 1
.= the scalar of X . [x,(f . (n + 1))] by A5, A8, A17, A19 ; :: thesis: verum
end;
end;
end;
hence ( 1 <= n + 1 & n + 1 <= len q implies g . (n + 1) = the scalar of X . [x,(f . (n + 1))] ) ; :: thesis: verum
end;
then A26: for n being Nat st S1[n] holds
S1[n + 1] ;
A27: for n being Nat holds S1[n] from NAT_1:sch 2(A12, A26);
1 <= len q by A1, A7, FINSEQ_1:6;
then g . (len q) = the scalar of X . [x,(f . (len q))] by A27
.= the scalar of X . [x,(f . (len p))] by A7, FINSEQ_1:6 ;
hence x .|. ( the addF of X "**" p) = addreal "**" q by A6, A11, BHSP_1:def 1; :: thesis: verum