Nyquist rate for sampling complex-valued data?

From: kiki (lunaliu3_at_yahoo.com)
Date: 11/12/04 

Date: Thu, 11 Nov 2004 18:49:42 -0800

I (vaguely) heard that sampling complex-valued data does not abide by the
Nyquist rate criteria, i.e., the sampling rate fs can go lower than Nyquist
rate and it still can avoid aliasing and reconstruct perfectly...

Is that true? Any theory behind it?

Thanks a lot