[Om] Tutorial or example collection for OpenMath?
Konrad Hinsen
konrad.hinsen at fastmail.net
Wed Feb 26 14:39:50 CET 2014
Alberto González Palomo writes:
> I'm not aware of any validation tool, but you can check the Simple
> Type System (STS) used for symbol signatures in the OM CDs.
> http://www.openmath.org/cd/sts.xhtml
Thanks, that looks interesting.
What's the status of these type signatures? Are they part of the CD,
and thus of the standard? I don't remember seeing any reference to
them in the OpenMath Standard 2.0.
> For instance, arith1:sum has:
>
> http://www.openmath.org/sts/arith1.xhtml#sum
That's bad news for me because it means I can't use OpenMath sums at
all for my application. Sums are defined only for Abelian monoids,
which excludes any expression containing floating-point numbers,
since floating-point addition is not associative. This is not
merely a theoretical concern as summation order definitely matters
in some of my use cases.
Exploring further, I note that arith1.plus also requires
commutativity. Is there any CD that covers floating-point arithmetic?
OpenMath does provide floating-point numbers, so there should also be
something one can do with them.
> For the double sum you mentioned, that would be nested:
A bit verbose but perfectly fine - if I didn't need those floats.
Francis Wright writes:
>> 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.
Lars explicitly referred to set1.cartesian_product, so I do have a
set. Reconsidering this, it wouldn't really help me because a
summation range defined by a set obviously implies that summation
order doesn't matter.
Konrad.
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