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 _______________________________________________ Om3 mailing list [email protected] http://openmath.org/mailman/listinfo/om3
