Let G=(V,E)be a simple graph and F be a subset of V.If the subgraph induced by the subset V-F does not contain cycles,then F is called a feedback set of G.The smallest value of the numbers of vertices in feedback sets is called the feedback number of G,denoted by f(G),that is,f(G)=min{|F|:F is a feedback set of G}.Caragiannis et al.obtained the upper bounds of the feedback number of 2-dimensional meshes.In this paper,we improve the upper bounds.
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