Title Disprove of a conjecture on the double Roman domination number Type of Research Article Keywords Disprove of a conjecture on the double Roman domination number Abstract Disprove of a conjecture on the double Roman domination number Researchers Zehui Shao (First Researcher)، Rana Khoeilar (Second Researcher)، hossein karami (Third Researcher)، Mustapha Chellali (Fourth Researcher)، Seyed Mahmoud Sheikholeslami Kavkani (Fifth Researcher)