0 votes 0 votes How many graphs in the above image is connected? I think it is (i) and (iii) but they are saying graph number (ii) is also connected. How? Anilava Kundu asked Nov 19, 2018 Anilava Kundu 517 views answer comment Share Follow See all 7 Comments See all 7 7 Comments reply Show 4 previous comments Anilava Kundu commented Nov 19, 2018 reply Follow Share I am not aware of this inequality but a graph is connected if there is a path from every vertice to another vertice 0 votes 0 votes HeartBleed commented Nov 19, 2018 reply Follow Share If a graph has more than e>(n−1)(n−2)2 then it is connected. This is not a mandatory condition for a graph to be connected. ( This condition is sufficient, but not necessary) If a graph is connected then e≥n−1. This is the mandatory condition. A connected graph must satisfy the condition that e≥n−1. ( This condition is necessary, but not sufficient) 0 votes 0 votes Naveen Kumar 3 commented Nov 19, 2018 reply Follow Share A graph is connected when there is a path between every pair of vertices. In (ii), vertices a and f are not connected to any other vertex. 1 votes 1 votes Please log in or register to add a comment.