[Om] Tutorial or example collection for OpenMath?

[Francis Wright]

>  > As for encoding a sum over all pairs of indices, there is the  > complication that
> the official OMCDs aren't fond of expressing  > things using binder symbols (even
> if the standard supports the  > concept of such), so one typically has to wrap the
> body up in a  > lambda before feeding it to a summation symbol; sort of like  >
> writing $\sum_{[a,b]} f$ rather than $\sum_{k=a}^b f(k)$. Thus we  > get
> 
> Thanks for the example. That's in fact the kind of information I was looking for:
> general design principles that help finding the right way to express things.
> 
> For the particular case of "sum", I find the definition in arith1 a bit vague:
> 
>    An operator taking two arguments, the first being the range of
>    summation, e.g. an integral interval, ...
> 
> There is no definition of "range of summation", just an example. You use a set in
> your example, which is fine, but there's nothing in the definition of "sum" that
> tells me that sets are a valid specification for a "range of summation".

If by "set" you mean the use of { } in the example above then I think that is part of the TeX syntax used to present the example and does not imply a set.

Francis