let a1, a2, a3, a4, a5, a6, a7, a8, a9 be object ; ( dom (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) = Seg 9 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 1 = a1 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 2 = a2 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 3 = a3 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 4 = a4 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 5 = a5 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 6 = a6 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 7 = a7 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 8 = a8 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 9 = a9 )
thus dom (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) =
Seg ((len <*a1,a2,a3,a4,a5,a6,a7,a8*>) + (len <*a9*>))
by FINSEQ_1:def 7
.=
Seg (8 + (len <*a9*>))
by Th19
.=
Seg (8 + 1)
by FINSEQ_1:40
.=
Seg 9
; ( (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 1 = a1 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 2 = a2 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 3 = a3 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 4 = a4 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 5 = a5 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 6 = a6 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 7 = a7 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 8 = a8 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 9 = a9 )
A1:
len <*a1,a2,a3,a4,a5,a6,a7,a8*> = 8
by Th19;
then
1 in dom <*a1,a2,a3,a4,a5,a6,a7,a8*>
by FINSEQ_3:25;
hence (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 1 =
<*a1,a2,a3,a4,a5,a6,a7,a8*> . 1
by FINSEQ_1:def 7
.=
a1
;
( (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 2 = a2 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 3 = a3 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 4 = a4 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 5 = a5 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 6 = a6 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 7 = a7 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 8 = a8 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 9 = a9 )
2 in dom <*a1,a2,a3,a4,a5,a6,a7,a8*>
by A1, FINSEQ_3:25;
hence (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 2 =
<*a1,a2,a3,a4,a5,a6,a7,a8*> . 2
by FINSEQ_1:def 7
.=
a2
;
( (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 3 = a3 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 4 = a4 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 5 = a5 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 6 = a6 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 7 = a7 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 8 = a8 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 9 = a9 )
3 in dom <*a1,a2,a3,a4,a5,a6,a7,a8*>
by A1, FINSEQ_3:25;
hence (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 3 =
<*a1,a2,a3,a4,a5,a6,a7,a8*> . 3
by FINSEQ_1:def 7
.=
a3
;
( (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 4 = a4 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 5 = a5 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 6 = a6 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 7 = a7 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 8 = a8 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 9 = a9 )
4 in dom <*a1,a2,a3,a4,a5,a6,a7,a8*>
by A1, FINSEQ_3:25;
hence (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 4 =
<*a1,a2,a3,a4,a5,a6,a7,a8*> . 4
by FINSEQ_1:def 7
.=
a4
;
( (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 5 = a5 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 6 = a6 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 7 = a7 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 8 = a8 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 9 = a9 )
5 in dom <*a1,a2,a3,a4,a5,a6,a7,a8*>
by A1, FINSEQ_3:25;
hence (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 5 =
<*a1,a2,a3,a4,a5,a6,a7,a8*> . 5
by FINSEQ_1:def 7
.=
a5
;
( (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 6 = a6 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 7 = a7 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 8 = a8 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 9 = a9 )
6 in dom <*a1,a2,a3,a4,a5,a6,a7,a8*>
by A1, FINSEQ_3:25;
hence (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 6 =
<*a1,a2,a3,a4,a5,a6,a7,a8*> . 6
by FINSEQ_1:def 7
.=
a6
;
( (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 7 = a7 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 8 = a8 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 9 = a9 )
7 in dom <*a1,a2,a3,a4,a5,a6,a7,a8*>
by A1, FINSEQ_3:25;
hence (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 7 =
<*a1,a2,a3,a4,a5,a6,a7,a8*> . 7
by FINSEQ_1:def 7
.=
a7
;
( (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 8 = a8 & (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 9 = a9 )
8 in dom <*a1,a2,a3,a4,a5,a6,a7,a8*>
by A1, FINSEQ_3:25;
hence (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 8 =
<*a1,a2,a3,a4,a5,a6,a7,a8*> . 8
by FINSEQ_1:def 7
.=
a8
;
(<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 9 = a9
len <*a9*> = 1
by FINSEQ_1:40;
then
1 in dom <*a9*>
by FINSEQ_3:25;
hence (<*a1,a2,a3,a4,a5,a6,a7,a8*> ^ <*a9*>) . 9 =
<*a9*> . 1
by A1, FINSEQ_1:def 7
.=
a9
;
verum