Dear Bo, you missed it a little.
If we have a measurable center point and no measurable line or a measurable line and no measurable center point, we cannot define a circle.
It means that if
r=0 or
r=oo we cannot use the circle’s concept, or in other words, we cannot define a circle.
r is circle’s radius.
s' is a dummy variable (
http://www.mathworld.wolfram.com/DummyVariable.html )
a) If
r=0 then
s'=|{}|=0 -> (no circle can be found) =
A
b) If
r>0 then
s'=|{
r}|=1 -> (a circle can be found) =
B
The connection between
A,
B states cannot be but
A_XOR_
B
Also
s' = 0 in case
(a) and
s' = 1 in case
(b), can be described as
s'=0_XOR_
s'=1.
We can prove that
A is the limit of
B only if we can show that
s'=0_AND_
s'=1 -> 1
A collection of elements, which can be found on many different scales, really approaching to some given constant, only if it has finitely many elements.
<u>Further explanation:</u>
0 and 1 are the cardinal values, and they are based on the set that standing in the base of each one of them.
If
r=0 then we use the Empty set in order to define the value of
s' = |{}| = 0 (because no circle can be found)
If
r>0 then we use a Non-empty set in order to define the value of
s' =|{
r}| = 1 (because a circle can be found)
A is a center of a circle iff
B is any measurable arbitrary value, which is not
A.
B can never be
A exactly as the cardinal of a non-empty set cannot be the cardinal of the empty set.
So we get
A XOR
B states which are equivalent to
s'=|{}| XOR
s'=|{
r}| states.
In this case
A cannot be the limit of
B.
QED.
A definition cannot include in it states where the thing that it defines DOES NOT EXIST, and the standard definition of a circle (
http://mathworld.wolfram.com/Circle.html ) includes in it states (
r=0,
r=oo) where no circle can be found.
Strictly specking, this definition cannot be considered as a rigorous logical definition.