[seqfan] Style sheet lacks much of anything on "vertical bar"

[Robert Munafo]

No-one noticed on oeis.org/wiki/Talk:Style_Sheet therefore I now ask here.

Can we add to the "Spelling_and_notation" section of
oeis.org/wiki/Style_Sheet, to sanction more uses of the vertical bar
"|"?

I happen to have looked for precedent specifically of the form
"min_{a|b} {expression}" and ran across the lack of clarity on whether
"|" can be used apart from set cardinality.

Searching the OEIS I find that "|" has been used for the "divides"
relation 10 or more years ago, e.g. in the formula for A117498 we
find: "min_{d|n, 1<d<n} a(d)+a(n/d)".

In the OEIS, for a similarly long amount of time, the bar has also
been used often for "such that", e.g. name of A071893 "Min{k |
A071891(k)=n}".

I would recommend these uses, in no particular order, as most seem to
be already in common use, usually in an unambiguous way:
  x|<expr> for "x divides an expression" (i.e. <expr>/x is an integer)
which could be a statement, or a set definition as when "written
below" Sigma or Pi or as a subscript to a function like "min"
  x|<statement> for "x such that <statement>" as might be used in a
set definition "for all x such that...", or existence assertion e.g.
"there exists x such that"
  |<expr>| for the absolute value of a scalar-valued expression or
field members for which something similar is well-defined
  ||<expr>|| for the norm of a vector-valued expression
  |M| for the determinant of a matrix
  |S| for the cardinality of a set S

and I would recommend against:
  <expr>|<expr> for bitwise "or" as in some programming languages
  <statement>||<statement> for boolean disjunction "or" as in some
programming languages

--
  Robert Munafo, mrob27 at gmail.com