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8
<
:
2a 1 d 1
LN .N 1/x 2 ;
x 1 .t C 1/ D .1 a 1 /x 1 .t/ C
T j D .1/ W
2a 2 d 2
LN x 1 .t/ .N 2/x 2 .t/ ;
x 2 .t C 1/ D .1 a 2 /x 2 .t/ C
and the equilibrium outputs are the solutions of the algebraic system
2d 1
LN .N 1/x 2 ;
x 1
D
2d 2
LN x 1 .t/ .N 2/x 2 .t/ ;
x 2
D
.1/ . The local asymptotic sta-
provided that these solutions are inside the region
D
.1/
bility of any equilibrium point inside region
D
is determined by the study of the
eigenvalues of the Jacobian matrix
0
1
2a 1 d 1 .N 1/
.LN .N 1/x 2 / 2
1 a 1
@
A
J .1/
D
:
2a 2 d 2
.LN x 1 .N 2/x 2 / 2 1 a 2 C
2a 2 d 2 .N 2/
.LN x 1 .N 2/x 2 / 2
computed at the equilibrium. However, boundary equilibria can also exist, located
in regions
.i / , i D 2;3;4. For example, in the region
.2/ , where the map assumes
D
D
the form
8
<
2a 1 d 1
LN .N 1/x 2 ;
x 2 .t C 1/ D .1 a 2 /x 2 .t/ C a 2 L;
x 1 .t C 1/ D .1 a 1 /x 1 .t/ C
T j D .2/ W
:
we can have a boundary equilibrium with coordinates E D .x 1 ;x 2 / D .2d 1 =L;L/
2 D
.2/ , provide d that x 2 < NL 2 2d 1
.N
NL 2
1
2d 2
and x 2 >
2 x 1 C
2/L . This holds if
p 2d 1 <L< p d 1 C d 2 . It is clear that if the equilibrium E exists, that is if the
above inequalities are satisfied, then it is locally asymptotically stable, because
inside the region
1/L
N
.N
.2/ the Jacobian matrix is triangular with eigenvalues .1 a 1 /
and .1 a 2 /. Similar arguments apply to the region
D
.3/ , where the map assumes
D
the form
x 1 .t C 1/ D .1 a 1 /x 1 .t/ C a 1 L;
x 2 .t C 1/ D .1 a 2 /x 2 .t/ C a 2 L;
and a boundary equilibrium of coordinates E 0 D x 0 1 ; x 0 2 D .L;L/ 2 D
T j D .3/ W
.3/
exists
x 0 2 > NL 2 2d 1
NL 2
2d 2
x 0 2 >
1
2 x 0 1
provided that
and
C
2/L , which imply that
.N
1/L
N
.N
L< min p 2d 1 ; p 2d 2 . Whenever these inequalities are satisfied, then the bound-
ary point .L;L/ is a locally asymptotically stable equilibrium, since the Jacobian
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