Information Technology Reference
In-Depth Information
have properties 1, 2, 5 and 6. Figure 3.2 shows the effect of transformations
T 1 , T 2 , T 3 and T 4 on the subset A
= (
1
,
4
) , (
2
,
2
) , (
2
,
3
) , (
2
,
4
) , (
3
,
3
) , (
3
,
4
) , (
3
,
7
) ,
(
4
,
2
) , (
4
,
4
) }
of the lattice
{
1
,
2
,
3
,
4
}×{
1
,
2
,...,
7
}
. It is also easy to see that
F = F,
=
,
,...,
.
T s
s
1
2
n
Therefore we can state the following theorems.
(
,
,
)
Theorem 2. Let
X
Y
M
be a game on a lattice satisfying
= F
T s Y
X
=
Y
,
(3.4)
M
(
T s A
,
T s B
)=
M
(
A
,
B
)
(
A
X
,
B
Y
,
s
=
1
,
2
,...
n
) .
An optimal strategy for player I is the uniform distribution on X .
1
|F| =
1
m n ,
x
(
A
)=
x F (
A
)=
A
X
.
(3.5)
Let B 0
Y such that
1
m n
A ∈F
(
x F ,
)=
(
,
)
min
B
M
B
min
M
A
B
Y
1
m n
A ∈F
=
M
(
A
,
B 0 )=
M
(
x F ,
B 0 ) .
(3.6)
Th us an optimal strategy for player II is the distribution on Y uniformly concentrated
in B 0 :
1
| ,
if B
B 0
|
B 0
y B 0 (
B
)=
(3.7)
0 f B
B 0
and the value of the game is M
(
x F ,
B 0 )
given by ( 3.6 ).
Proof. Since properties 1-6 of tr an sfor m a tions T s
work h ere, we can apply
= X
M the set X
Theorem 1 . In the associated game G
,
Y
,
= {F}
contains the
only element
which will be the o pt imal strategy for player I. The optimal strategy
for player II will be a pure strategy B 0 such that
F
M F,
B =
M F,
B 0 .
m i B
The two strategies x F ,
y B 0
are obtained from the two optimal strategies
F
, B 0 ,of
the associated game G , completing the proof.
 
Search WWH ::




Custom Search