[texhax] Some questions on math mode

[Philip TAYLOR (Ret'd)]

P. R. Stanley wrote:
 >> P. R. Stanley wrote:
 >>> Hi folks
 >>> 1. What effect does placing a letter [A-Za-z] in math mode produce,
 >>> for example $x$ $A$?
 >> It sets the letter in maths italic, which is similar
 >> to (but not the same as) text italics.
 >>
 >>> Sorry to be a pain, what is the difference between math italic and
 >>> text italic? Where would one use math italic? For examplem is it
 >>> for something as undane as a variable -- $ xy$?

Yes, certainly for variables : the problem is that
one needs to be a mathematician (or at least to have
more than a passing familiarity with maths notation)
to know when italics are called for and when not.
It is easier to differentiate between maths italic
and text italic : the latter is simply for use in
non-mathematical text whenever italics are called for.

And in case you are uncertain exactly how italics
differ from more conventional, so-called "Roman",
letters, italics are slanted to the right by a few
degrees, but are re-drawn so that they are more ornate
that a simple slanting of the Roman text would give.

** Phil.