0 votes 0 votes Definition of valid matching says that if every vertex is incident with atmost one vertex then it is a matching but I have seen coaching material note which includes null graph as a matching.I am confused please help. Graph Theory graph-theory discrete-mathematics + – sripo asked Sep 28, 2018 sripo 384 views answer comment Share Follow See 1 comment See all 1 1 comment reply Shaik Masthan commented Sep 28, 2018 reply Follow Share yes, Null graph ( but all vertices should be present in that graph) is a Matching for any graph. in Null graph, degree of each vertex is 0 as per Matching condition, the degree of each vertex ≤ 1 ===> Null graph satisfies 0 votes 0 votes Please log in or register to add a comment.