4n1rudh4's blog

By 4n1rudh4, history, 3 years ago, In English

Let a 'nice' set S of a graph be a set of vertices such that if v is in S then all neighbors of v in G are not in S. It should also cover all the vertices. That is there should not be any vertex that is neither part of the set S nor neighbor of some element in S.

How can we find a nice set with a minimum size for an undirected graph?

The original problem was about finding such 'nice' set for a tree which could be solved with a greedy approach (choosing all vertices which are parents of leaf nodes and removing the last 3 levels). I am wondering how to calculate such a set for an undirected graph?

Following strategies will not work: 1. Choosing vertex with maximum connectivity and adding it to set S and removing it and all neighbors of v 2. Generating BFS tree and choosing alternate levels 3. Generating BFS tree from maximum degree vertex/ choosing levels with minimum vertices

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3 years ago, # |
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I think I'm being dumb, but for such a set of minimal size, can't you just take 1 node?

What you might actually be asking for is the "maximum independent set". [Here is the wikipedia on this](https://en.wikipedia.org/wiki/Independent_set_(graph_theory)).

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3 years ago, # |
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If I am not wrong, this is the min vertex cover problem.

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    3 years ago, # ^ |
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    correct me if I am wrong but this article explains min vertex problem but the example given is not as per my specifications.  check the last example both 4 and 2 are in the vertex cover. But I am asking when no 2 adjacent vertices are in cover. So ideal answer should be {4,0}

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      3 years ago, # ^ |
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      That's minimum independent dominating set.