Why does the branch cut for log(1+z), cutting away the negative axis, start at -1?
I am really confused about this concept.
Is it because from -1 to 0, the inputs (1+z) are just viewed as inputs that aren't actually from the negative axis at all, and so log(1+z) is well-defined and continuous on (-1,0]? I don't see the single-valuedness on (-1,0], though. Shouldn't log(1+z) jump by a term, on (-1,0]?
Any comments are welcome.
Thanks,