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\centerline{\bf STANFORD UNIVERSITY}
\centerline{\bf DEPARTMENT OF STATISTICS}
\centerline{\big DEPARTMENTAL SEMINAR}
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\centerline{4:15 p.m., Tuesday, September 26, 2000}
\centerline{Sequoia Hall Rm. 200}
\centerline{(Cookies at 3:45 in 1st Floor Lounge)}

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\centerline{\sl David B. Wilson}
\centerline{\sl Microsoft research}
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\centerline{\bf Mixing times of lozenge tiling and card shuffling Markov chains}
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We introduce a simple technique that can be applied to a number of classes
of Markov chains to obtain upper and lower bounds on their mixing times.
One application is to a class                             
of Markov chains introduced by Luby, Randall, and Sinclair to generate
random tilings of regions by lozenges.  In another application we resolve a
few questions raised by Diaconis and Saloff-Coste, by lower bounding the
mixing time of various card shuffling Markov chains.  Our bounds are
optimal up to a constant factor. 
  
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