a − r, |y| < a − r} K
1
P (K
1
) =
µ(K
1
)
µ(K)
=
4(a−r)
2
4a
2
= (1−
r
a
)
2
µ(·)
K = {(x, y)| |x| 6 2, |y| 6 2}
A(x, y) min{|x|, |y|} 6
1
K = {(x, y)| |x| 6 1, |y| 6 1}
A(x, y)
y = x
K = {(x, y)| |x| 6 2, |y| 6 2}
A(x, y)
max{|x|, |y|} 6 1
K = {(x, y)| |x| 6 2, |y| 6 2}
A(x, y) min{|x|, |y|} >
1
K = {(x, y)| |x| 6 2, |y| 6 2}
A(x, y)
max{|x|, |y|} > 1
K = {(x, y)| |x| 6 2, |y| 6 2}
A(x, y)
max{|x|, |y|} 6 min{|x|, |y|}
K = {(x, y)|
x
2
4
+ y
2
= 1}
A(x, y)
OX
1
Ω