Posting Guidelines

- The topic must be consistent with the goals and activities of the
Northwestern University Math Problem Solving Group.
- When posting a solution (or hint, or suggestion...) concerning a
new problem, include a statement of the problem - not just a
reference.
- Give others a chance to participate and learn. Don't just send a
final complete solution to a problem. If you have a solution,
announce it and send first some hints on how you arrived to it,
inviting others to work the problem by themselves. If you send a
partial or complete solution it is a good idea to add some narrative
illustrating your thoughts while working on the problem, so that
others can take advantage of your learning experience.
- Postings must be carefully written and easy to read. Although
linguistic limitations are understandable and expected, try to use
complete sentences written in correct English and check your messages
for spelling mistakes.
- Write your messages in plain text (e.g. no html formating) and without attachments.

**These are some recommendations and examples about how to write
mathematical formulas in plain text:**

- Arithmetic expressions, relations . . . :
addition/subtraction: a + b, a - b. multiplication: a b, a * b. division: a/b. powers, superscripts: x^y = x raised to the y-th power, or x superscript y. subscripts: x_n, x_{n}, x[n] = x subscript n. relations: > (greater than), < (less than), >= (greater than or equal to), =< (less than or equal to), != (different), <> (different).

- Functions:
sqrt(x) = square root of x sin(x) = sine of x

- Sums, products, integrals, limits...
sum for n=a to b of a_n product for n=a to b of a_n integral between a and b of f(x) dx limit as x -> infinity of f(x)

- Special constants, Greek letters, etc.: just write the name:
`e, pi, alpha, aleph, Omega, infinity...` - Sets: Some especial sets like the set of real numbers are usually
written with a letter in blackboard font. In plain text use the
same letter, perhaps clarifying its meaning, e.g.: "
`for x in R (real numbers)...`"

Example of set:`{x in R | x > 3} = set of elements x in R such that x > 3`.

Other conventions like TeX, Maple, Mathematica, etc., are also acceptable; e.g.:

lim_{n \to \infty} 1/n = 0

(but keep in mind that some readers may not be familiar with them.)

Comments, suggestions...? email Miguel A. Lerma at: mlerma at math dot northwestern dot edu

WWW Address: "https://www.math.northwestern.edu/~mlerma/problem_solving/posting-guidelines.html"