let n be non zero Nat; (n + 1) -BinarySequence (2 to_power n) = (0* n) ^ <*TRUE*>
0* n in BOOLEAN *
by Th4;
then
0* n is FinSequence of BOOLEAN
by FINSEQ_1:def 11;
then reconsider 0n = 0* n as Tuple of n, BOOLEAN ;
now for i being Nat st i in Seg (n + 1) holds
((n + 1) -BinarySequence (2 to_power n)) . i = (0n ^ <*TRUE*>) . ilet i be
Nat;
( i in Seg (n + 1) implies ((n + 1) -BinarySequence (2 to_power n)) . i = (0n ^ <*TRUE*>) . i )assume A1:
i in Seg (n + 1)
;
((n + 1) -BinarySequence (2 to_power n)) . i = (0n ^ <*TRUE*>) . inow ((n + 1) -BinarySequence (2 to_power n)) . i = (0n ^ <*TRUE*>) . iper cases
( i in Seg n or i = n + 1 )
by A1, FINSEQ_2:7;
suppose A2:
i in Seg n
;
((n + 1) -BinarySequence (2 to_power n)) . i = (0n ^ <*TRUE*>) . ithen A3:
i >= 1
by FINSEQ_1:1;
i <= n + 1
by A1, FINSEQ_1:1;
then
i - 1
<= (n + 1) - 1
by XREAL_1:9;
then A4:
i -' 1
<= (n + 1) - 1
by A3, XREAL_1:233;
n =
(n - (i -' 1)) + (i -' 1)
.=
(n -' (i -' 1)) + (i -' 1)
by A4, XREAL_1:233
;
then A5:
2
to_power n = (2 to_power (n -' (i -' 1))) * (2 to_power (i -' 1))
by POWER:27;
i in Seg (len 0n)
by A2, CARD_1:def 7;
then A6:
i in dom 0n
by FINSEQ_1:def 3;
n >= i
by A2, FINSEQ_1:1;
then
n + 1
> i
by NAT_1:13;
then
n > i - 1
by XREAL_1:19;
then
n - (i - 1) > 0
by XREAL_1:50;
then
n - (i -' 1) > 0
by A3, XREAL_1:233;
then
n -' (i -' 1) > 0
by A4, XREAL_1:233;
then consider n1 being
Nat such that A7:
n -' (i -' 1) = n1 + 1
by NAT_1:6;
reconsider n1 =
n1 as
Nat ;
A8: 2
to_power (n -' (i -' 1)) =
(2 to_power n1) * (2 to_power 1)
by A7, POWER:27
.=
(2 to_power n1) * 2
by POWER:25
;
2
to_power (i -' 1) > 0
by POWER:34;
then A9:
((2 to_power n) div (2 to_power (i -' 1))) mod 2 =
(2 to_power (n -' (i -' 1))) mod 2
by A5, NAT_D:18
.=
0
by A8, NAT_D:13
;
i in Seg (len ((n + 1) -BinarySequence (2 to_power n)))
by A1, CARD_1:def 7;
then
i in dom ((n + 1) -BinarySequence (2 to_power n))
by FINSEQ_1:def 3;
hence ((n + 1) -BinarySequence (2 to_power n)) . i =
((n + 1) -BinarySequence (2 to_power n)) /. i
by PARTFUN1:def 6
.=
IFEQ (
(((2 to_power n) div (2 to_power (i -' 1))) mod 2),
0,
FALSE,
TRUE)
by A1, Def1
.=
0
by A9, FUNCOP_1:def 8
.=
0n . i
by A2, FUNCOP_1:7
.=
(0n ^ <*TRUE*>) . i
by A6, FINSEQ_1:def 7
;
verum end; end; end; hence
((n + 1) -BinarySequence (2 to_power n)) . i = (0n ^ <*TRUE*>) . i
;
verum end;
hence
(n + 1) -BinarySequence (2 to_power n) = (0* n) ^ <*TRUE*>
by FINSEQ_2:119; verum