Re: content mark-up: operators vs. relations?

> Wouldn't this strip apply of some of its power to capture semantics?
> Will <apply> become like a open paren and <apply/> like a close paren,
> generic in the sense of serving as a container for either functional or
> relation expressions?

I don't think any semantics is lost. Especially if you view relations as
boolean valued functions, the difference between a relation and a
function is somewhat hard to detect. Even if you view relations as
distinct from functions, the current restrictions mean that
<= is a relation and so used with reln, but
if you were to construct the operation `< or =' from `<' `=' and `or'
then the result is not considered to be a relation any more and so would
be applied with apply not reln.

`relations' such as < usually get rather different rendering rules than
binary operations such as +. but a MathMl renderer does not need the
reln/apply distinction to detect this, as the renderer anyway needs
to know any special layout requirements of each mathml content