BOWLING GREEN STATE UNIVERSITY
          DEPARTMENT OF MATHEMATICS AND STATISTICS CALENDAR
 
                      Week of March 31 - April 4

Tuesday, April 1

 2:30 PM  STATISTICS SEMINAR  - Room 459 MSC
          Pranab K. Sen, Distinguished Lukacs Professor, BGSU. 

Wednesday, April 2
      
 3:45 PM  STATISTICS AND PROBABILITY SEMINAR  - Room 300 MSC
          Grace Montepiedra, Applied Statistics and Operations Research, BGSU.

Thursday, April 3

 2:30 PM  SCIENTIFIC COMPUTATION SEMINAR  - Room 459 MSC
          Panayot Vassilevski, BGSU and Bulgarian Academy of Sciences
          "Preconditioning non-symmetric and indefinite problems"
          Abstract: In this talk a general approach of preconditioning
            non--symmetric and possibly indefinite problems will be
            presented. It relies on a subspace correction idea;
            namely, by solving at every iteration a coarse problem one
            can essentially use any available preconditioner for the
            principal spd part of the original problem, now in a
            subspace form.  Similar idea can be used for
            preconditioning problems discretized on grids with local
            refinement.

Friday, April 4

 3:30 PM  Coffee
 3:45 PM  COLLOQUIUM  - Room 459 MSC
          Panayot Vassilevski, BGSU and Bulgarian Academy of Sciences
          "Iterative solution of elliptic PDE exploiting hierarchy of
           discretizations"
          Abstract: In this talk the topic of fast solution of large
            linear systems of algebraic equations will be addressed,
            by first pointing out the specifics of the problems coming
            from discretization of typical elliptic partial
            differential equations. A main class of iterative schemes
            that come naturally from the discretization method will
            then be outlined. Those in particular include the
            hierarchical basis method and multigrid. The methods can
            be formulated and analyzed in a joint framework giving
            rise to well known Gauss--Seidel iterative methods of
            block type where each block corresponds to a subspace (or
            a grid). Some numerical illustration will also be given.


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