set V = R ^* n;
hence
R ^* n is Abelian
by RLVECT_1:def 2; ( R ^* n is add-associative & R ^* n is right_zeroed & R ^* n is right_complementable )
now for x, y, z being Element of the carrier of (R ^* n) holds (x + y) + z = x + (y + z)let x,
y,
z be
Element of the
carrier of
(R ^* n);
(x + y) + z = x + (y + z)reconsider u =
x,
v =
y,
w =
z as
Element of
n -tuples_on the
carrier of
R by DEF;
H:
y + z =
(vector_add (n,R)) . (
v,
w)
by DEF
.=
v + w
by Defa
;
x + y =
(vector_add (n,R)) . (
u,
v)
by DEF
.=
u + v
by Defa
;
hence (x + y) + z =
(vector_add (n,R)) . (
(u + v),
w)
by DEF
.=
(u + v) + w
by Defa
.=
u + (v + w)
by Lm2
.=
(vector_add (n,R)) . (
u,
(v + w))
by Defa
.=
x + (y + z)
by H, DEF
;
verum end;
hence
R ^* n is add-associative
by RLVECT_1:def 3; ( R ^* n is right_zeroed & R ^* n is right_complementable )
hence
R ^* n is right_zeroed
by RLVECT_1:def 4; R ^* n is right_complementable
hence
R ^* n is right_complementable
by ALGSTR_0:def 16; verum