The 20 Questions Seminar

The 20 questions seminar Pablo Solis and I started two weeks ago (see below) is now happening every Tuesday afternoon.  We’ll be updating the following wiki each week (on Tuesdays or Wednesdays, if we can manage) with a fresh batch of hopefully interesting questions:

http://scratchpad.wikia.com/wiki/20qs

Many generous responses from users here at the secret blogging seminar have already been incorporated there.  The wiki is free for mathematicians everywhere to post questions and answers of their own — there is a section for questions from outside the seminar.  Our inspiration is the following:

Once in a while, we’ll all come upon a question that screams “this is easy to someone else, but who?”  On the other hand, we like to hear questions that are easy for us but hard for others, so we can be useful.  So why not trade, and trade fast?  Rule #1 at the seminar is:

“1. Avoid asking questions that require a lot of background, like from your own research.  Stick to questions you think others are at least as prepared for as you are.”

When people follow it, this rule results in questions that are fun and accessible, and you often end up with answers, too.  But since usually the “poser” is the only one really interested in the answer — at least at first — we have adopted the following:

“2. Wait until the end of the seminar to discuss solutions, unless of course you can say the answer very quickly :)”

This keeps the seminar from degenerating to a dialogue about one question, which I think is the natural tendency. And just so everyone feels welcome, we have:

“3. You do not have to ask or answer a question! Just hearing what lots of people are thinking in a short time is reason enough to attend.”

I think these three ideas, someone recording the questions, and a critical mass of curious mathematicians are all that’s needed for a successful “Questions Seminar”, though time will be the only test.

In the meantime, here are last week’s questions, to be followed by next week’s (on Tuesday):
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