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 ...

This is a preview. Log in through your library . Abstract A non-backtracking walk on a graph, H, is a directed path of directed edges of H such that no edge is the inverse of its preceding edge.

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 ...

Back in the hazy olden days of the pre-2000s, navigating between two locations generally required someone to whip out a paper map and painstakingly figure out the most optimal route between those ...