You mean instead of the pseudo LaTeX math-mode ? I did describe it in words first... But, I will try to give a more succinct definition-in-words : Between a pa

You mean instead of the pseudo LaTeX math-mode ? I did describe it in words first... But, I will try to give a more succinct definition-in-words : Between a pair of a (partial) function from one preordered set to another, which is surjective and order preserving, along with a pre-composition inverse which is both order preserving and order reflecting. (except instead the relations on the sets being a preorder, I'd rather it just be transitive, rather than transitive and reflexive). Is that really more clear than the pseudo-LaTeX ? I'm not sure.