ByElle Pop

The Configuration Space of Two Particles Moving on a Graph
663KbAbstractIn this thesis we study the conguration space, F (, 2), of two particles moving without collisions on a graph with a view to calculating the Betti numbers of this space. We develop an intersection theory for cycles in graphs inspired by the classical intersection theory for cycles in manifolds and we use this to develop an algorithm to calculate the second Betti number of F (,2) for any graph. We also use this intersection theory to provide a complete description of the cohomology algebra H ^(F (, 2), Q) for any planar graph and site:9to5mac.com apple hermes band replica to calculate explicit formulae for the Betti numbers of F (, 2) when is a complete graph or a complete bipartite graph. We also investigate the generators of group H_2 (F (, 2), Z) and show that for any planar graph this group is entirely generated by tori induced by disjoint cycles in the graph. For non planar graphs the situation is more complicated and we show that there can exist a generator of H_2 (F (, 2), Z) which is not the fundamental class of a surface embedded in the space F (, 2).

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