TY - JOUR ID - Ghareghani2020 LB - Ghareghani2020 AU - Ghareghani, Narges AU - Peterin, Iztok AU - Sharifani, Pouyeh TI - A note on bipartite graphs whose [1,k]-domination number equal to their number of vertices ST - A note on bipartite graphs whose [1,k]-domination number equal to their number of vertices JO - Opuscula Math. JA - Opuscula Math. JF - Opuscula Mathematica PY - 2020 VL - 40 IS - 3 SP - 375 EP - 382 DO - https://doi.org/10.7494/OpMath.2020.40.3.375 UR - https://doi.org/10.7494/OpMath.2020.40.3.375 AB - A subset \(D\) of the vertex set \(V\) of a graph \(G\) is called an \([1,k]\)-dominating set if every vertex from \(V-D\) is adjacent to at least one vertex and at most \(k\) vertices of \(D\). A \([1,k]\)-dominating set with the minimum number of vertices is called a \(\gamma_{[1,k]}\)-set and the number of its vertices is the \([1,k]\)-domination number \(\gamma_{[1,k]}(G)\) of \(G\). In this short note we show that the decision problem whether \(\gamma_{[1,k]}(G)=n\) is an \(NP\)-hard problem, even for bipartite graphs. Also, a simple construction of a bipartite graph \(G\) of order \(n\) satisfying \(\gamma_{[1,k]}(G)=n\) is given for every integer \(n \geq (k+1)(2k+3)\). KW - domination KW - \([1,k]\)-domination number KW - \([1,k]\)-total domination number KW - bipartite graphs SN - 1232-9274 ER -