[net.puzzle] Balls in the bowl: One Last time.

stekas@hou2g.UUCP (J.STEKAS) (03/02/84)

>The numbered-balls argument gives an ambiguous answer to the (100 in, 1 out)
>problem because the PROBLEM is faulty, not because the ANALYSIS is faulty.

Ok, Dave.  I yield to your loquacious ventings, but there are problems with
both our methods as apllied to this problem.

Since the # of balls is well defined only on [11:59, 12:00), taking
the limit can't tell me what the state is at 12:00.  But the numbering
technique cannot be used unless the precise order of removing the balls
is known,  and that information wasn't available (faulty probelm?).

Of course, unless your Alice in Wonderland you won't run up against
such a problem too often.

                                             Jim

Pucc-H:Pucc-I:ags@CS-Mordred.UUCP (03/02/84)

>  Since the # of balls is well defined only on [11:59, 12:00), taking
>  the limit can't tell me what the state is at 12:00.  But the numbering
>  technique cannot be used unless the precise order of removing the balls
>  is known,  and that information wasn't available (faulty probelm?).

You almost have it, but there is one small point.  It is true that the
order of removal was not specified, which is precisely what makes the
problem ill-defined.  The very purpose of the numbered-balls argument
was to point out that the order of removal makes a difference.

Many people have been claiming that the answer has something to do
with an infinite series (100-1) + (100-1) + ..., in which "terms
can be rearranged to get different answers".  This explanation is
invalid for two reasons:

   1.  The value of an infinite series can be defined only in terms of
       the limit of partial sums, and I have already pointed out that
       limits have nothing to do with the Balls in the Bowl Problem.

   2.  The infinite series argument fails to explain why the (1 in, 1 out)
       version of the problem has a unique answer, which the numbered-balls
       technique handles successfully.

One last variation on the problem to think about:  what happens in the
(1 in, 1 out) version if the bowl is not initially empty?
-- 

Dave Seaman
..!pur-ee!pucc-i:ags

"Against people who give vent to their loquacity 
by extraneous bombastic circumlocution."