§ Example of Non Commuting Summation
Consider the 2D region:
|...
|1 1 1 1 1
|1 1 1 1 -1
|1 1 1 -1 -1
|1 1 -1 -1 -1
|1 -1 -1 -1 -1 ...
+---------
Ie, we have a "diamond" of 1s:
|...
|* * * * *
|* * *
|* * *
|* *
|*
+---------
- If we add up each of the x axes first, we see that it adds up to
-infinity
, so then when we add up the sums, we get -infinity
. - On the other hand, each of the y axes has infinitey many
*
s (1s) if we start adding from the bottom, so they will "wash over" the finite number of blank spaces (-1s), meaning that each y axis