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Re: setDec and forbidden interval/decoration combinations

Vincent
 I prefer your last selection
Am 22.11.2013 12:26, schrieb Vincent Lefevre:

The current draft (8.1, 2013-10-25) says in §11.5.2:

   Given an interval x and a decoration dx, the operation setDec(x, dx)
   returns the decorated interval x_dx if this is an allowed combination.
   The cases of forbidden combinations are as follows:
   - setDec(Empty, dx) where dx is one of def, dac or com returns NaI.
   - setDec(x, com), for any unbounded x, returns Entire_dac.
   - setDec(x, ill) for any x, whether empty or not, returns NaI.

I think that the 3rd item is obvious. But the first two items do not
seem to be consistent. I would have chosen either:

   - setDec(Empty, dx) where dx is one of def, dac or com returns NaI.
   - setDec(x, com), for any unbounded x, returns NaI.

so that any forbidden combination gives NaI, or


this one

   - setDec(Empty, dx) where dx is one of def, dac or com returns Empty_trv.
   - setDec(x, com), for any unbounded x, returns Entire_dac.

to set the decoration to the maximum allowed one in both cases.

Any comment?

an empty interval is a set-base interval
 Jürgen


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