[Om3] [Fwd: ISSUE-33 (statistical symbols): Kyle's Siegrist's request for new Content-MathML symbol]

[Professor James Davenport]

On Fri, October 24, 2008 5:10 pm, Paul Libbrecht wrote:
>
> Le 24-oct.-08 à 12:09, Professor James Davenport a écrit :
> so we would make the whole of combinat1 in MathML-cd-group?
I don't see why? The original author merely wanted to beable to express
this is MathML (as opposed to the case where it COULD already be expressed
in MathML, and MathML3 had to preserve this expressibility. My informal
understanding of the MathML CD group was "all the CDs needed to express
the (pragmatic->strict versions of the) MathML-C in MathML 2".
>>> 2. Permutation coefficient:  n(n -1)...(n - k + 1), usually
>>> rendered P(n, k) or nPk or (n)k.
>> Personally, I've always written n!/k!, but if there's a call for it, I
>> could always add it to combinat1.
>
> Looks like it's common so it's probably needed in combinat1.
True. Michael - can you ask your student who's working on OM3 CDs to do
this, since he's probably more up-to-date with the tools than I am at the
moment.
>>> 3. A probability operator with an optional "given" construction
>>> (for conditional probability).  Typical rendering would be
>>>    P(A, B, ...) (without conditioning) or  P(A, B, ... | C, D, ...)
>>> (with conditioning).
>> For the monadic versions P(A), or P(A|C D ...) I have no problem: I
>> assume
>> their absence is due to the fact that we never had a probabilist on
>> board
>> in OM. I assume the proposers P(A, B, ...) is P(A&B&...), and we MIGHT
>> want to see that represented explicitly.
>
> I've never seen the "," sepped version (though been TA in such branch,
> shame on me!).
I think that adds to my question.
>>> 4. An expected value operator with an optional "given" construction
>>> (for conditional expected value).  Typical rendering would be E(A,
>>> B, ...) (without conditioning) or  E(A, B, ... | C, D, ...) (with
>>> conditioning).
>> Again, I hace no problem with E(A) or E(A|C ...).
>> I have no idea what is meant by E(A,B).
>
> You can measure expectation on any event, can't you?
Yes, but what is the 'event'. What do you understand by
E(height,weight|elephant)? The tuple (3m, 9500kg)? In that case, how is
this different from the tuple (E(height|elephant),E(weight|elephant))?
Note that I'm not saying there's a good rason against it, merely that I
haven't seen a good reason for it.

James Davenport
Hebron & Medlock Professor of Information Technology
Formerly RAE Coordinator and Undergraduate Director of Studies, CS Dept
Lecturer on CM30070, 30078, 50209, 50123, 50199
Chairman, Powerful Computing WP, University of Bath
OpenMath Content Dictionary Editor
IMU Committee on Electronic Information and Communication