Re: 1-1/2+1/3-1/4+1/5-1/6+1/7



On Feb 12, 5:58 am, Han de Bruijn <Han.deBru...@xxxxxxxxxxxxxx> wrote:
Gonçalo Rodrigues wrote:


Is that your pavlovian response whenever you see some mathematics that
is beyond your understanding? That it is an unnecessary complication?

Geez! In my _finitary_ comprehension, the whole thing is sooo obvious !
But that's not the game I want to play here. Therefore I'm _begging_ you
to employ a formalism which is as simple and straghtforward as possible
and not invoke unneccessary complications / generalizations or whatever.


It's quite simple and natural: according to the proposed definitions,
given a sequence of sets (A_1, A_2, ..., A_n, ...) we say that

If there is an n such that element a is never in /any/ A_m for m > n,
then a must /not/ be in the limit set.

If there is an n such that element a is always in /every/ A_m for m >
n, then a must be in the limit set.

If there are elements a such that neither of the above two cases hold,
then the limit set is not well-defined.

Example application:

If you remove a ball from the vase at time t before noon, and at no
time t1 > t do you return the ball to the vase, then the ball is not
in the vase at noon.

If you put a ball in the vase at time t before noon, and at no time t1
t do you remove it, then the ball is still in the vase at noon.

If neither of the above cases hold for a particular ball, then "the
ball is in the vase at noon" is undefined for that ball; and therefore
"the set of balls in the vase at noon" is undefined.

Cheers - Chas

.



Relevant Pages

  • Re: An uncountable countable set
    ... The only critical time dependency is that each ball to be inserted shall ... the vase is empty at noon of anything of any balls ... An affirmative answer confirms that the vase is empty at noon. ... given the times of insertions and removals. ...
    (sci.math)
  • Re: An uncountable countable set
    ... The mathematics used in the balls and vase problem ... Each ball is put into the vase at a specific ... You think to maniuplate limits in your argumentst. ...
    (sci.math)
  • Re: An uncountable countable set
    ... labelled ball, for example the ball labelled 15, is in the vase at that ... That seems contradictory to me. ... If we had an upper bound on the set of naturals, then if n is a natural ...
    (sci.math)
  • Re: An uncountable countable set
    ... -1/n, where n is a natural number, there are balls in the vase. ... for which we can say "that ball was placed in the vase at time t". ... You cannot proceed to noon without inserting infinite balls, and you cannot empty the vase before noon. ... The only times which may proceed using only finite naturals are those finitely before noon, but at none of those times does the vase empty. ...
    (sci.math)
  • Re: An uncountable countable set
    ... -1/n, where n is a natural number, there are balls in the vase. ... But that *alone* does not even include every time t before noon; ... for which we can say "that ball was placed in the vase at time t". ... though that can be surmised from the insertion and removal ...
    (sci.math)

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