Let A be a 0 âˆ’ 1 matrix with precisely two 1â€™s in each column and let 1 be the all-one vector. We show that the problems of deciding whether the linear system Ax â‰¥ 1, x â‰¥ 0 (1) defines an integralâ€¦ (More)

We obtain a necessary and su cient condition for tournaments to possess a min-max relation on packing and covering directed cycles, together with strongly polynomial time algorithms for the feedbackâ€¦ (More)

Combinatorial optimization games deal with cooperative games for which the value of every subset of players is obtained by solving a combinatorial optimization problem on the resources collectivelyâ€¦ (More)

Grillet established conditions on a partially ordered set under which each maximal antichain meets each maximal chain. Berge pointed out that Grilletâ€™s theorem can be stated in terms of graphs, madeâ€¦ (More)

A tree of rings is an undirected graph obtained from a tree by replacing each node of th with a cycle (called tree-node-cycle) and then contracting the edges of the tree so that two corresponding toâ€¦ (More)

It is proved in this paper that every bipartite graphic sequence with the minimum degree Î´ â‰¥ 2 has a realization that admits a nowhere-zero 4-flow. This result implies a conjecture originallyâ€¦ (More)

A graph G is called cycle Mengerian (CM) if for any nonnegative integral function w de ned on V (G), the maximum number of cycles in G such that each vertex v is used at most w(v) times is equal toâ€¦ (More)