set TR = TOP-REAL n;
set G = GFuncs the carrier of (TOP-REAL n);
let f be Function of (TOP-REAL n),(TOP-REAL n); ( f is base_rotation implies ( f is homogeneous & f is additive & f is rotation & f is being_homeomorphism ) )
assume
f is base_rotation
; ( f is homogeneous & f is additive & f is rotation & f is being_homeomorphism )
then consider F being FinSequence of (GFuncs the carrier of (TOP-REAL n)) such that
A1:
f = Product F
and
A2:
for k being Nat st k in dom F holds
ex i, j being Nat ex r being Real st
( 1 <= i & i < j & j <= n & F . k = Mx2Tran (Rotation (i,j,n,r)) )
;
defpred S1[ Nat] means ( n <= len F implies for g being Function of (TOP-REAL n),(TOP-REAL n) st g = Product (F | n) holds
( g is homogeneous & g is additive & g is being_homeomorphism & g is rotation ) );
A3:
for m being Nat st S1[m] holds
S1[m + 1]
proof
let m be
Nat;
( S1[m] implies S1[m + 1] )
assume A4:
S1[
m]
;
S1[m + 1]
set m1 =
m + 1;
reconsider P =
Product (F | m) as
Function of
(TOP-REAL n),
(TOP-REAL n) by MONOID_0:73;
assume A5:
m + 1
<= len F
;
for g being Function of (TOP-REAL n),(TOP-REAL n) st g = Product (F | (m + 1)) holds
( g is homogeneous & g is additive & g is being_homeomorphism & g is rotation )
1
<= m + 1
by NAT_1:11;
then A6:
m + 1
in dom F
by A5, FINSEQ_3:25;
then consider i,
j being
Nat,
r being
Real such that A7:
( 1
<= i &
i < j &
j <= n )
and A8:
F . (m + 1) = Mx2Tran (Rotation (i,j,n,r))
by A2;
reconsider M =
Mx2Tran (Rotation (i,j,n,r)) as
Element of
(GFuncs the carrier of (TOP-REAL n)) by MONOID_0:73;
A9:
F | (m + 1) = (F | m) ^ <*M*>
by A6, A8, FINSEQ_5:10;
let g be
Function of
(TOP-REAL n),
(TOP-REAL n);
( g = Product (F | (m + 1)) implies ( g is homogeneous & g is additive & g is being_homeomorphism & g is rotation ) )
assume A10:
g = Product (F | (m + 1))
;
( g is homogeneous & g is additive & g is being_homeomorphism & g is rotation )
A11:
g =
(Product (F | m)) * M
by A9, A10, GROUP_4:6
.=
(Mx2Tran (Rotation (i,j,n,r))) * P
by MONOID_0:70
;
A12:
Mx2Tran (Rotation (i,j,n,r)) is
rotation
by A7, Lm7;
(
P is
homogeneous &
P is
additive &
P is
being_homeomorphism &
P is
rotation )
by A4, A5, NAT_1:13;
hence
(
g is
homogeneous &
g is
additive &
g is
being_homeomorphism &
g is
rotation )
by A11, A12, Lm8, TOPS_2:57;
verum
end;
A13:
F | (len F) = F
by FINSEQ_1:58;
A14:
S1[ 0 ]
for m being Nat holds S1[m]
from NAT_1:sch 2(A14, A3);
hence
( f is homogeneous & f is additive & f is rotation & f is being_homeomorphism )
by A1, A13; verum