Асимптотические оценки. Мицик М.Ф. - 13 стр.

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( )( )
0|Re
0
=
+
=
= tytxt
yUxUtzS
dt
d
.

constzS
)(Im

γ
, 
()( )
0|Im
0
=
+
=
= tytxt
yVxVtzS
dt
d

=
+
=
+
0
0
tytx
tytx
yVxV
yUxU

( )
xyyx
VUVU
=
=
,

=
=
+
.0
0
tytx
tytx
xUyU
yUxU

( )
0
2
22
=
+
=
ttt
zyx
, 

(
)
(
)
(
)
(
)
0
0000
=
=
=
=
zVzVzUzU
yxyx
.

γ

0
z
, 
0)(
0
=
zS
.
, 
.
 4. (.) 

( )
zU

D

D
. 
( )
zU
, 
.
 5.
0
z

)(zS
, .
0)(,0)(
00
=
zSzS
. 
U

0
z

)(Re)(Re
0
zSzS =
, 

0
z

U
. 
( )
)()(Re
0
zSzS
, , 
)(Re)(Re
0
zSzS <
, 
γ
, 
, .
)(Re)(Re
0
zSzS <
)(Im)(Im
0
zSzS =

∈γz
.
                              Re S (z (t )) |t =0 = U ′x xt′ + U ′y yt′ = 0 .
                           d
                           dt
                  Im S ( z ) ≡ const           γ∗,

                              Im S ( z (t )) |t = 0 = V x′xt′ + V y′ y t′ = 0
                           d
                           dt

                           U ′x xt′ + U ′y yt′ = 0
                            ′ ′
                            Vx xt + V y′ yt′ = 0
                                                     (U ′ = V ′, U ′ = −V ′)
                                                        x        y     y           x

                           U ′x xt′ + U ′y yt′ = 0
                            ′ ′
                           U x yt − U ′y xt′ = 0 .
                                                            (              )
                                                ∆ = − xt′2 + yt′2 = − zt′ ≠ 0 ,
                                                                                       2




                  U ′x ( z0 ) = U ′y ( z0 ) = Vx′( z0 ) = V y′ ( z0 ) = 0 .
                                           γ∗
z0 ,                 S ′( z 0 ) = 0 .
                                                                                               ,
                                           .
                    4. (                                                                                          .)
              U (z )
D                              D.              U (z )                                              ,
                                                                                                                             .
                    5.              z0 –                                                               S (z ) ,        .
S ′( z 0 ) = 0, S ′′( z 0 ) ≠ 0 .                                              U                   z0
Re S ( z ) = Re S ( z0 )                                                       ,
         z0                                           U                                    .
Re(S ( z ) − S ( z0 ) )                                                    ,                                ,
Re S ( z ) < Re S ( z0 ) ,                                            γ∗,
              ,     . Re S ( z ) < Re S ( z0 )              Im S ( z ) = Im S ( z 0 )                             z ∈γ ∗ .