An approximation algorithm for the total covering problem
We introduce a 2-factor approximation algorithm for the minimum total covering number problem.
We introduce a 2-factor approximation algorithm for the minimum total covering number problem.
In this paper we propose a structural characterization for a class of bipartite graphs defined by two forbidden induced subgraphs. We show that the obtained characterization leads to polynomial-time algorithms for several problems that are NP-hard in general bipartite graphs.
Let be a prime, and let be the Fermat quotient of to base . The following curious congruence was conjectured by L. Skula and proved by A. Granville In this note we establish the above congruence by entirely elementary number theory arguments.