let m be non empty Element of NAT ; for x, a being Element of REAL
for i being Element of NAT st 1 <= i & i <= m holds
Replace (0* m),i,(a * x) = a * (Replace (0* m),i,x)
let x, a be Element of REAL ; for i being Element of NAT st 1 <= i & i <= m holds
Replace (0* m),i,(a * x) = a * (Replace (0* m),i,x)
let i be Element of NAT ; ( 1 <= i & i <= m implies Replace (0* m),i,(a * x) = a * (Replace (0* m),i,x) )
assume A1:
( 1 <= i & i <= m )
; Replace (0* m),i,(a * x) = a * (Replace (0* m),i,x)
A2:
( len (Replace (0* m),i,(a * x)) = m & len (Replace (0* m),i,x) = m )
by Lm6;
then A3:
len (a * (Replace (0* m),i,x)) = len (Replace (0* m),i,(a * x))
by RVSUM_1:147;
for j being Nat st 1 <= j & j <= len (Replace (0* m),i,(a * x)) holds
(Replace (0* m),i,(a * x)) . j = (a * (Replace (0* m),i,x)) . j
proof
let j be
Nat;
( 1 <= j & j <= len (Replace (0* m),i,(a * x)) implies (Replace (0* m),i,(a * x)) . j = (a * (Replace (0* m),i,x)) . j )
assume A4:
( 1
<= j &
j <= len (Replace (0* m),i,(a * x)) )
;
(Replace (0* m),i,(a * x)) . j = (a * (Replace (0* m),i,x)) . j
reconsider j =
j as
Element of
NAT by ORDINAL1:def 13;
per cases
( i = j or i <> j )
;
suppose A5:
i = j
;
(Replace (0* m),i,(a * x)) . j = (a * (Replace (0* m),i,x)) . jthen (Replace (0* m),i,(a * x)) . j =
a * x
by A1, Lm7
.=
a * ((Replace (0* m),i,x) . j)
by A1, A5, Lm7
;
hence
(Replace (0* m),i,(a * x)) . j = (a * (Replace (0* m),i,x)) . j
by RVSUM_1:66;
verum end; suppose A6:
i <> j
;
(Replace (0* m),i,(a * x)) . j = (a * (Replace (0* m),i,x)) . jthen
(Replace (0* m),i,x) . j = 0
by A2, A4, Lm7;
then
(Replace (0* m),i,(a * x)) . j = a * ((Replace (0* m),i,x) . j)
by A2, A4, A6, Lm7;
hence
(Replace (0* m),i,(a * x)) . j = (a * (Replace (0* m),i,x)) . j
by RVSUM_1:66;
verum end; end;
end;
hence
Replace (0* m),i,(a * x) = a * (Replace (0* m),i,x)
by A3, FINSEQ_1:18; verum