let D, D9, E be non empty set ; :: thesis: for d1 being Element of D
for d9 being Element of D9
for F being Function of [:D,D9:],E
for p being FinSequence of D st p = <*d1*> holds
F [:] (p,d9) = <*(F . (d1,d9))*>

let d1 be Element of D; :: thesis: for d9 being Element of D9
for F being Function of [:D,D9:],E
for p being FinSequence of D st p = <*d1*> holds
F [:] (p,d9) = <*(F . (d1,d9))*>

let d9 be Element of D9; :: thesis: for F being Function of [:D,D9:],E
for p being FinSequence of D st p = <*d1*> holds
F [:] (p,d9) = <*(F . (d1,d9))*>

let F be Function of [:D,D9:],E; :: thesis: for p being FinSequence of D st p = <*d1*> holds
F [:] (p,d9) = <*(F . (d1,d9))*>

let p be FinSequence of D; :: thesis: ( p = <*d1*> implies F [:] (p,d9) = <*(F . (d1,d9))*> )
assume A1: p = <*d1*> ; :: thesis: F [:] (p,d9) = <*(F . (d1,d9))*>
A2: p . 1 = d1 by A1;
reconsider r = F [:] (p,d9) as FinSequence of E by Th81;
len p = 1 by A1, FINSEQ_1:39;
then A3: len r = 1 by Th82;
then 1 in Seg (len r) ;
then 1 in dom r by FINSEQ_1:def 3;
then r . 1 = F . (d1,d9) by A2, FUNCOP_1:27;
hence F [:] (p,d9) = <*(F . (d1,d9))*> by A3, FINSEQ_1:40; :: thesis: verum