Abstract. In this paper, the following problem is considered: does there exist a 𝑡-arc-transitive regular covering graph of an 𝑠-arc-transitive graph for positive integers 𝑡 greater than 𝑠? In ...

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Graph theory isn’t enough. The mathematical language for talking about connections, which usually depends on networks — vertices (dots) and edges (lines connecting them) — has been an invaluable way ...

When you get stuck on a fiendishly difficult sudoku, it’s hard not to wonder if the puzzle really has a solution. At another moment, aglow in the triumph of a clever deduction, you might have a ...