Some conferences usually have rump sessions and some usually do not. By asking around (not always reliable) I have found that STOC, FOCS, SoCG usually do not have rump sessions but that CCC, Crypto, Eurocrypt, AsiaCrypt, AfricaCrypt, TCC (Theory of Cryptography Conference), FSE (Fast Software Encryption) usually do have rump sessions. (A different question, dealt with in Jon Katz's Aug 7 blog is are there too many crypto conferences. That post and the comments on it also list more crypto conferences.) I would like commenters to correct and add to this list.
- I do not know where the term Rump Session comes from. I first heard it from Alan Selman at the first CCC business meeting, though he used it as though it was a common term. If you Google the term you get around 19,000 hits, mostly things like 2007 Crypto Rump Session
- At a big conference a Rump Session might be harder to organize. That may explain why STOC, FOCS don't have them, but CRYPTO is pretty big and does, while SoCG is small and doesn't.
- Early on Rump sessions were on a blackboard. Now many of the Rump sessions are prepared polished presentations. I am tempted to say that this means they are planned ahead of time and can't be things worked on at the conference, but actually people can now whip up polished presentations pretty fast.
- Rump sessions are a good way to communicate informal unpolished ideas and ask for help on formalizing or polishing them. And for help on the hard math as well. I think that conferences should have them, though I realize that there may be logisiticaly problems.
- Should you share your open problems with others so openly? If you want them solved and don't care if you are the one who solves them then YES. Frank Stephan and Martin Kummer solved an open problem that I proposed at a COLT Rump Session. They got a paper out at the next COLT where I was acknowledged. I was happy that my problem got solved.
- Why do some conferences have it and others do not? My guess is the usual one Because we've always had (not had) them. Also, I suspect that the XXX-CRYPTO conferences have them because the first one, CRYPTO, had it.
- What do non-theory Comp Sci Conferences do? How about outside of theory? In fields where they do not have prestige conferences perhaps many talks are what we call rump sessions.