x
0
= x(t
0
) t → ±∞
dx
j
/dx
k
= Φ(x
1
, x
2
, . . . , x
N
) j = 1, 2, . . . , k − 1, k + 1, . . . , N
x
k
F (x)
f
j
(x) = 0 j = 1, 2, . . . , N
n
n
N 2n = N
¨x + ω
2
0
x = 0 .
ω
0
= 1
x
1
= x, x
2
= ˙x
ω
2
0
x
2
1
2
+
x
2
2
2
= H(x
1
, x
2
) = const.
H(x
1
, x
2
)