Well, what do you know? I write an entry about complex numbers and the next thing that happens is my blog editor breaks down and I get an error message "cannot take the log of -1 at lib/MT/Template/ContextHandlers.pm line 2032". Our nice support people have fixed it now, so hopefully I am readable again.
For those of you that don’t see the mathematical irony, the log of -1 is a complex number. (Logs tell you what power to raise 10 to in order to get your number; so log 1000 is 3, log 100 is 2, log 10 is 1, log 1 is zero, log 0.1 is -1 etc etc, but there is no real log of -1. Logs of negative numbers are complex.)