<p>I plan on writing my personal essay on my math activities and research. If I write about things like the USAMO, PROMYS and other math events/organizations, can I assume that the admissions officers know what I am talking about? Or do I have to constantly describe what math contests and math organizations are?</p>
<p>Depends on the university. Anyone applying to HYPSM, Duke, Caltech, Harvey Mudd and the like should have no worries. Beyond this point, I would at least not give just the acronym without the expansion. "United States of America Mathematical Olympiad" is likely to inspire at least some curiousity in the minds of overworked adcoms.</p>
<p>Never use unspelled abbreviations, ever.
The general rule is to spell it out the first time you mention it, include abbreviation, and later on use abbreviation if you need to. For example:
I want to apply to the University of Chicago (UC). Once at UC, I plan.....</p>
<p>In addition to explaining the abbreviation, should I be adding descriptions like:</p>
<p>I was preparing for the United States pf America Mathematical Olympiad (USAMO), which is a contest where only 300 students are invited to participate...</p>
<p>You should if the school in question's not HYPSD or something like that. Keep it to a sentence or two though.</p>
<p>anyone else?</p>