Sparse Graphs With Local Covering Conditions on Edges
Debsoumya Chakraborti, Amirali Madani, Anil Maheshwari, Babak Miraftab · Journal of Graph Theory · 2026
ABSTRACT In 1988, Erdős suggested the question of minimizing the number of edges in a connected ‐vertex graph where every edge is contained in a triangle. Shortly after, Catlin, Grossman, Hobbs, and Lai resolved this in a stronger form. In this paper, we study a natural generalization of the question of Erdős in which we replace “triangle” with “clique of order ” for . We completely resolve this generalized question with the characterization of all extremal graphs. Motivated by applications in data science, we also study another generalization of the question of Erdős where every edge is required to be in at least triangles for instead of only one triangle. We completely resolve this problem for with the characterization of all extremal graphs.