[seqfan] Re: New Printer's Errors from JMF

[Joshua Zucker]

On Thu, Feb 19, 2009 at 4:22 AM, Richard Mathar
<mathar at strw.leidenuniv.nl> wrote:
> This is ill-defined, because it does not specify the associative rules
> (=implicit parentheses). These are part of any higher
> programming language, neither evident nor universal. For this reason
> they need to be defined in detail.

I think that if it's not specified, one would assume that the usual
order of operations applies -- it seems to be a widely-enough used
convention.  But more clarity is always worthwhile!

> Take the example of 2^3^4 (which some people think is well-defined,
> though it isn't). See my comment in A145021.

I think that there's a well-enough established convention that 2^3^4
means 2^(3^4) that in the absence of evidence to the contrary, I'd
assume that meaning.  So I think it's well-defined, though I agree
it's a matter of definition (or convention), not of mathematical
logic, to take the definition that I do.  What makes you say that it
isn't well-defined?

And of course more clarity on these matters is always useful
communication!  Your comment in A145021 is definitely helpful in
reading that entry.

--Joshua Zucker