M. Aizenman, J.H. Schenker, R.M. Friedrich, and D.Hundertmark.
Constructive Fractional-Moment Criteria for 
Localization in Random Operators
(107K, LaTex, using Elsevier "elsart" files (attached).)

ABSTRACT.  We present a family of finite-volume criteria which cover the 
regime of exponential decay for the fractional moments of Green 
functions of operators with random potentials. 
Such decay is a technically convenient characterization of 
localization for it is known to imply spectral localization, 
absence of level repulsion, dynamical localization and a 
related condition which plays a significant role in the 
quantization of the Hall conductance in two-dimensional Fermi gases. 
The constructive criteria also preclude fast power-law decay of 
the Green functions at mobility edges.