[Om] Tutorial or example collection for OpenMath?

[Konrad Hinsen]

Dear all,

I discovered OpenMath a while ago and I am trying to figure out how to
use it. The documentation looks quite complete in the sense of
defining the meaning of OpenMath objects, but what I need is the
inverse: find out how to encode a certain formula in OpenMath. In
theory, I could study all the content dictionaries, but I'd probably
give up before completing that task.

So what I am looking for is either a tutorial, or at least a list of
examples. I don't need anything particularly exotic, but I don't even
see immediately how to express something like "a sum over all pairs of
indices".

Version 2.0 of the OpenMath standard refers to "OpenMath primer" at
http://www.openmath.org/standard/primer/, but the contents are a bit
disappointing.

For a bit of background information, I intend to use OpenMath for
describing potential energies in molecular modelling. I am working on
a data model for computational chemistry
(http://mosaic-data-model.github.io/), which is to molecular modelling
what OpenMath is to maths: a data model with multiple encodings
designed for exchanging data between programs.

Konrad.