<br>                   BINGHAMTON GEOMETRY/TOPOLOGY SEMINAR<br><div class="gmail_quote"><div class="gmail_quote"><div class="gmail_quote"><div class="gmail_quote"><div class="gmail_quote"><div class="gmail_quote"><div class="gmail_quote">
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<br><i>Date:</i>  Tuesday, Sep 13, 2011<br>


<i>Time:</i>  2:50-3:50pm<br><i>Place:</i>  Library North 2205 followed by coffee/tea in the Anderson Reading Room.<br>

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<i>Speaker:</i>  Jean-Francois Lafont (The Ohio State University)<br><i>Title:</i> Isomorphism versus commensurability<em></em><div><i></i>
      <i><br>Abstract:</i> 
I will describe two classes of finitely presented
groups. In the first class, the isomorphism problem is
solvable, but the commensurability problem is unsolvable.
In the second class, the commensurability problem is
solvable, but the isomorphism problem is unsolvable.
This is joint work with Goulnara Arzhantseva and Ashot
Minasyan.   
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