# [om] A Proposal for extending OpenMath with structure sharing

jhd at cs.bath.ac.uk jhd at cs.bath.ac.uk
Thu Apr 4 12:47:47 CEST 2002

On Wed, 3 Apr 2002, Andrew Solomon wrote:
> I have no idea what subtraction of intervals is (probably a
> deficiency in my real analysis education).
If X and Y are intervals, X-Y = [x-y: x \in X y \in Y]
> So, if someone would be so kind, I would like to have:
> an example of syntactic sharing, an example of semantic sharing, and
Syntactic sharing occurs in Maple, so that if I type
X:=interval(-1,1);Y:=interval(-1,1); # intending two independent variables
then in fact X and Y will point to the same object.

Semantic sharing occurs in several specialised interval systems, where if
X and Y pointe dot the same interval, that tels the system that they ARE
the same variable. In such a system X-x => [0,0], whereas X-Y => [-1,1]
> an explanation of where they differ.
I hope the above helps.
James
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