let n be non zero Nat; Product (ppf n) = n
defpred S1[ Nat] means for n being non zero Nat st support (ppf n) c= Seg $1 holds
Product (ppf n) = n;
A1:
support (ppf n) = support (pfexp n)
by Def9;
A2:
S1[ 0 ]
A6:
for k being Nat st S1[k] holds
S1[k + 1]
proof
let k be
Nat;
( S1[k] implies S1[k + 1] )
assume A7:
S1[
k]
;
S1[k + 1]
let n be non
zero Nat;
( support (ppf n) c= Seg (k + 1) implies Product (ppf n) = n )
assume A8:
support (ppf n) c= Seg (k + 1)
;
Product (ppf n) = n
A9:
support (ppf n) = support (pfexp n)
by Def9;
per cases
( not support (ppf n) c= Seg k or support (ppf n) c= Seg k )
;
suppose A10:
not
support (ppf n) c= Seg k
;
Product (ppf n) = nset p =
k + 1;
set e =
(k + 1) |-count n;
set s =
(k + 1) |^ ((k + 1) |-count n);
then A15:
k + 1 is
Prime
by A9, Th34;
then A16:
k + 1
> 1
by INT_2:def 4;
then
(k + 1) |^ ((k + 1) |-count n) divides n
by Def7;
then consider t being
Nat such that A17:
n = ((k + 1) |^ ((k + 1) |-count n)) * t
;
reconsider s =
(k + 1) |^ ((k + 1) |-count n),
t =
t as non
zero Nat by A17;
A18:
dom (ppf s) = SetPrimes
by PARTFUN1:def 2;
(pfexp n) . (k + 1) = (k + 1) |-count n
by A15, Def8;
then A19:
(k + 1) |-count n <> 0
by A9, A11, PRE_POLY:def 7;
reconsider s1 =
s,
t1 =
t as non
zero Nat ;
A20:
support (ppf t) = support (pfexp t)
by Def9;
A21:
support (ppf t) c= Seg k
s1,
t1 are_coprime
proof
set u =
s1 gcd t1;
A29:
s1 gcd t1 divides t1
by NAT_D:def 5;
s1 gcd t1 <> 0
by INT_2:5;
then A30:
0 + 1
<= s1 gcd t1
by NAT_1:13;
assume
s1 gcd t1 <> 1
;
INT_2:def 3 contradiction
then
s1 gcd t1 > 1
by A30, XXREAL_0:1;
then
s1 gcd t1 >= 1
+ 1
by NAT_1:13;
then consider r being
Element of
NAT such that A31:
r is
prime
and A32:
r divides s1 gcd t1
by INT_2:31;
s1 gcd t1 divides s1
by NAT_D:def 5;
then
r divides s1
by A32, NAT_D:4;
then
r divides k + 1
by A31, Th5;
then
(
r = 1 or
r = k + 1 )
by A15, INT_2:def 4;
then
k + 1
divides t1
by A31, A32, A29, NAT_D:4;
then
k + 1
in support (pfexp t)
by A15, Th37;
then
k + 1
<= k
by A20, A21, FINSEQ_1:1;
hence
contradiction
by NAT_1:13;
verum
end; then A33:
ppf n = (ppf s) + (ppf t)
by A17, Th58;
consider f being
FinSequence of
COMPLEX such that A34:
Product (ppf s) = Product f
and A35:
f = (ppf s) * (canFS (support (ppf s)))
by Def5;
support (ppf s) = support (pfexp s)
by Def9;
then A36:
support (ppf s) = {(k + 1)}
by A15, A19, Th42;
then f =
(ppf s) * <*(k + 1)*>
by A35, FINSEQ_1:94
.=
<*((ppf s) . (k + 1))*>
by A11, A18, FINSEQ_2:34
;
then A37:
Product (ppf s) =
(ppf s) . (k + 1)
by A34
.=
s
by A15, A19, Th59
;
then A40:
support (ppf s) misses support (ppf t)
;
Product (ppf t) = t
by A7, A21;
hence
Product (ppf n) = n
by A17, A40, A33, A37, Th19;
verum end; end;
end;
A41:
for k being Nat holds S1[k]
from NAT_1:sch 2(A2, A6);