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== Title ==
 
== Title ==
Profit Maximization of Seller over Social Markets
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Property Testing in Planar Graphs and Euclidean Facility Location in the Streaming Model
    
== Speaker ==
 
== Speaker ==
Hamid Mahini, Postdoctoral Research, University of Maryland
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Morteza Monemizadeh
    
== Abstract ==
 
== Abstract ==
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We show that there is a novel and simple decomposition of an input point set P into small subsets P_i, such that:
 
We show that there is a novel and simple decomposition of an input point set P into small subsets P_i, such that:
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1- the cost of solving the facility location problem for each P_i is small (which means that for each P_i one needs to open only a small, polylogarithmic number of facilities),
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1- the cost of solving the facility location problem for each P_i is small (which means that for each P_i one needs to open only a small, polylogarithmic number of facilities),
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2- sum_i opt(P_i) \le (1+eps)  opt(P), where for a point set P, opt(P) denotes the cost of an optimal solution for P.
2- sum_i opt(P_i) \le (1+eps)  opt(P), where for a point set P, opt(P) denotes the cost of an optimal solution for P.
      
Using this decomposition we obtain two main results:
 
Using this decomposition we obtain two main results:
    
  1- A (1+eps)-approximation algorithm with running time  O(n log^2 n loglog n) for any constant eps.
 
  1- A (1+eps)-approximation algorithm with running time  O(n log^2 n loglog n) for any constant eps.
      
  2- The first (1+eps)-approximation algorithm for  the cost of the facility location problem for dynamic geometric data streams, i.e., when the stream consists of insert and delete operations of points from a discrete space [1,\dots,Delta]^2. The streaming algorithm uses poly(log Delta/eps) space.
 
  2- The first (1+eps)-approximation algorithm for  the cost of the facility location problem for dynamic geometric data streams, i.e., when the stream consists of insert and delete operations of points from a discrete space [1,\dots,Delta]^2. The streaming algorithm uses poly(log Delta/eps) space.