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=
X 1 ×
X 1 ×···×
in further considerations the Cartesian product X
X n (considered
as a n-tuple x i of variables x j describing characteristic features of the element u i )
[69, 150, 151].
The concept of the Cartesian product may be applied not only to the set U but
also to the algorithm Al g .
Itmeans that through the algorithm Al g = (
, wemay consider decomposition
of this algorithm, applying the concept of the Cartesian product to the algorithm Al g ,
or to the set of states of the algorithm U .
U
,
F
)
2.4.1 The Decomposition of an Algorithm Based
on the Cartesian Product Versus
Problem of Autonomy
Let us consider the Cartesian product X
=
X 1 ×
X 2 ×···×
X m , where the set X is
associated with the set U . Considering the function F :
u k
u k + 1
F
(
) =
(2.9)
and using the notation
u k
corresponds x k
u k + 1
corresponds x k + 1
,
,
(2.10)
x k + 1
1
x k + 1
2
where x k
x 1 ,
x 2 ,...,
x m ),
x k + 1
x k + 1
m
)
it is noticeable that the partial function F may be replaced with the function (also
partial) f
= (
= (
,
,...,
X whose domain is the set defined on the basis of characteristic
features. The function f is defined by
:
X
x 1 ,
x 2 ,...,
x m ) = (
x k + 1
1
x k + 1
2
x k + 1
m
u k
u k + 1
f
(
,
,...,
)
F
(
) =
.
(2.11)
In further considerations without the loss of generality we may limit the decompo-
sition of the set U into only to two sets X 1 and X 2 . The constraint to only two sets does
not limit further considerations and all of the significant problems may be further
successfully analyzed. The set X is the Cartesian product of two sets X
X 2 .
This limitation may be treated as the result of grouping the elements of the Carte-
sian product: X
=
X 1 ×
=
X 1 ×
X 2 , where X 1 =
X 1 ×
X 2 ×···
X i , X 2 =
X i + 1 ×
X i + 2 ×···
X m
(Fig. 2.3 ).
The projection of the set X onto the set X 1 and X 2 may be introduced by
Proj 1 :
X 1 ×
X 2
X 1 ( x 1 , x 2 ) X 1 × X 2
Proj 1 (
x 1 ,
x 2 ) =
x 1
(2.12)
Proj 2 :
X 1 ×
X 2
X 2 ( x 1 , x 2 ) X 1 × X 2
Proj 2 (
x 1 ,
x 2 ) =
x 2
The decomposition may now come down to the fact that it is necessary to form two
component algorithms Al g 1 and Al g 2 as in Fig. 2.4 . For this reason, it is necessary to
 
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