[Om] Question concerning OpenMath encoding

[David Carlisle]

On 25/03/2010 07:51, Heeren, Bastiaan wrote:
> Hello,
>
> I have a silly question about the OpenMath encoding, and the symbols defined in the list1 dictionary in particular. Suppose I want to represent the empty list with the n-ary symbol list1.list. Should that be:
>
>     <OMA><OMS cd='list1' name='list' /></OMA>
>
> or just:
>
>     <OMS cd='list1' name='list' />
>
> In case both are correct, would you consider one to be better than the other one?
>
> I could not figure out the correct encoding from the online documentation. To me, it seems strange to have an application without arguments to the function. On the other hand, if you are expecting a list, it is more regular to have the<OMA>  surrounding the list symbol.
>

You should use the OMA form. That is the list constructor applied to 
form an empty list while the second form is the list constructor itself 
(unapplied) so it is a valid Om expression but it denotes the function 
term rather than the empty list obtained by applying that function to no 
arguments.

David

________________________________________________________________________
The Numerical Algorithms Group Ltd is a company registered in England
and Wales with company number 1249803. The registered office is:
Wilkinson House, Jordan Hill Road, Oxford OX2 8DR, United Kingdom.

This e-mail has been scanned for all viruses by Star. The service is
powered by MessageLabs. 
________________________________________________________________________