Frederic Klopp (Paris-13): 

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TITLE: The bottom of the spectrum and Lifshitz tails for non-monotonous 
alloy type models.
	
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SUBTITLE: a random walk in an environment with traps that are
neither attractive nor repulsive.


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ABSTRACT:
For a standard alloy or Anderson type random
perturbations of the free Laplace operator, it is well known
that Lifshitz tails occur at the bottom of the spectrum when
the single site potential is sign definite. In this work, we
shall present some results in the case when the single site
potential is not sign definite. The talk is based on joint
work with S. Nakamura (Univ. Tokyo).