Re: Motions 5 and 6 under discussion --
J. Wolff v. Gudenberg schrieb:
a short note on motion 6 section 3 .5.2
last paragraph:
"we treat [-oo.-oo] and [oo,oo] as having no meaning (rather than
being empty)"
This sentence introduces a 3rd kind of emptyness, emptyset and NaI are
the first 2
No. It is not a kind of empty set, but a semantically forbidden
construct, since by definition, a lower bound is never +oo,
and an upper bound never -oo.
I suggest to drop this sentence and replace it by:
"Note that no operation ever returns [-oo.-oo] or [oo,oo]"
This is another consequence of the definition, since each operation
returns an interval, and [-oo.-oo] or [oo,oo] are not intervals in
the sense of the proposal.
I know that this would mean to set 1/0 or Log(0) equal to the emptyset
and not to infinity, that is exactly what was intended.
Yes. This is another consequence of the definition,
Arnold Neumaier