n n n n
h t a b
f t
X s
x t X s
s X s s X s
s s
X s s s
s X s sX s X s
X s s s s s s s
s X s X s s
X s s s s s
x t t t
s X s s X s s s
sX s s s s s s s
s X s sX s X s s
X s s s s s s s s s s
x t e-t et
sX s X s Y s
sY X Y
s X s X s Y s
s Y s X s s
X s s s s
sX s X s Y
s Y s X s Y s
s s s s
X s s s s s s s s s
at at
s a k
e kt e kt
s a k s a k
L L
a k
t
tt
f t e d e e
t
tt
f t e d e e
t
t
tt dt d t t
f t d
t
f t kt F s s k
f t kt F s k s k
f t tneat f t ntneat atneat
Lntneat atneat s Ltneat
at at
n t e e
s a s a s a s a
L L
f t t kt f
f t kt kt kt
k
ks k k F s s F s
Lt kt F s s k
s k
f t t kt f
f t kt kt kt
kt t kt
k k s k
kt kt kt
k k s k k s k
L
a b
f t u t u t u t a u t b
tntn = n
jnn n
s F s ns n
n
e
g t
g t f t
g t f t
g t f t
f
n
t n f t
Lts
Lt e t
s
t t t t