With the move of MathOverflow into the SE network, this account is now associated with accounts in math.SE and other sites in the network. While I plan to continue my (generally low-level) participation in MO, my current plans do not include restarting my very heavy prior participation in those other sites. Please do not send me private e-mail to call my attention to matters related to those sites. Thank you. Also, I do not wish to be sent, by private e-mail, questions that you can just as well ask on those sites. I would have thought it was obvious, but apparently I need to say so explicitly. ©