A counterexample to a conjecture of Jafari Rad and Volkmann
Mostafa Blidia, Mustapha Chellali · Communications in combinatorics and optimization · 2022
In this short note, we disprove the conjecture of Jafari Rad and Volkmann that every γ-vertex critical graph is γR-vertex critical, where γ(G) and γR(G) stand for the domination number and the Roman domination number of a graph G, respectively.