Your tetrit position paper

[John Pryce <j.d.pryce@xxxxxxxxxxxx>]

Nate, P1788

On 22 Apr 2010, at 17:49, Nate Hayes wrote:
> Attached is a position paper I'd like to share with everyone for discussion.

Thanks for writing this. I will shortly vote No to motion 15 and will say that one thing needed to make me vote Yes is an extended Rationale listing actual applications that show decoration properties in use, so as to justify the definitions we make, etc. Your B&B example should be included in full.

On p5, "such f(X') will be recursively bisected", I think f(X') should be X'.

Your basic table in 2.2, and similarly in your emails about this:
>   Rank    Tetrit        Description
>   3         (T,F)        Everywhere true
>   2         (T,T)        Somewhere true, somewhere false
>   1         (F,T)        Everywhere false
>   0         (F,F)        Nowhere true, nowhere false

This is not correct because "Everywhere true/false" doesn't exclude the empty set. (Because (all x in Empty) P(x) is always true.) It needs to be
  Rank    Tetrit        Description
  3         (T,F)        Somewhere true, nowhere false
  2         (T,T)        Somewhere true, somewhere false
  1         (F,T)        Nowhere true, somewhere false
  0         (F,F)        Nowhere true, nowhere false

("nowhere Q" is the same as "everywhere !Q" so, arbitrarily, I've removed "everywhere" in favour of "nowhere".)

You can't get away from each line containing TWO assertions.

John