The ROC is a ring or disk centered at the origin
DTFT exists if and only if the ROC includes the unit circle
The ROC cannot contain any poles
The ROC for finite-length sequence is the entire z-plane
except possibly z=0 and z=?
The ROC for a right-handed sequence extends outward from
the outermost pole possibly including z= ?
The ROC for a left-handed sequence extends inward from the
innermost pole possibly including z=0
The ROC of a two-sided sequence is a ring bounded by poles
The ROC must be a connected region
A z-transform does not uniquely determine a sequence without
specifying the ROC