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Q: When does a graph becomes a tree?
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Prove that a graph G is connected and only if it has a spanning tree?

Proving this is simple. First, you prove that G has a spanning tree, it is connected, which is pretty obvious - a spanning tree itself is already a connected graph on the vertex set V(G), thus G which contains it as a spanning sub graph is obviously also connected. Second, you prove that if G is connected, it has a spanning tree. If G is a tree itself, then it must "contain" a spanning tree. If G is connected and not a tree, then it must have at least one cycle. I don't know if you know this or not, but there is a theorem stating that an edge is a cut-edge if and only if it is on no cycle (a cut-edge is an edge such that if you take it out, the graph becomes disconnected). Thus, you can just keep taking out edges from cycles in G until all that is left are cut-gees. Since you did not take out any cut-edges, the graph is still connected; since all that is left are cut-edges, there are no cycles. A connected graph with no cycles is a tree. Thus, G contains a spanning tree. Therefore, a graph G is connected if and only if it has a spanning tree!


When the value of the slope gets smaller the graph gets?

As the slope get closer to zero, the graph becomes close to horizontal.


What is a rooted tree in graph theory?

A tree in which one vertex called the root, is distinguished from all the others is called a rooted tree.


When the value of a slope gets bigger the graph of a line gets?

As the slope gets bigger the graph becomes closer to vertical - from bottom left to top right.


What are the names of the on a graph?

bar graph, double bar graph, line graph, and picto graph

Related questions

An undirected graph becomes what when it is connected and contains no cycles or self loops?

Tree (since tree is connected acyclic graph)


Is every tree a graph or every graph a tree?

true


Is every tree a bipartite graph?

No, not every tree is a bipartite graph. A tree is a bipartite graph if and only if it is a path graph with an even number of nodes.


What is Difference between tree and spanning tree?

A tree is a connected graph in which only 1 path exist between any two vertices of the graph i.e. if the graph has no cycles. A spanning tree of a connected graph G is a tree which includes all the vertices of the graph G.There can be more than one spanning tree for a connected graph G.


Is tree a connected acyclic graph?

Every tree is a connected directed acylic graph.


Prove that a graph G is connected if and only if it has a spanning tree?

Proving this is simple. First, you prove that G has a spanning tree, it is connected, which is pretty obvious - a spanning tree itself is already a connected graph on the vertex set V(G), thus G which contains it as a spanning sub graph is obviously also connected. Second, you prove that if G is connected, it has a spanning tree. If G is a tree itself, then it must "contain" a spanning tree. If G is connected and not a tree, then it must have at least one cycle. I don't know if you know this or not, but there is a theorem stating that an edge is a cut-edge if and only if it is on no cycle (a cut-edge is an edge such that if you take it out, the graph becomes disconnected). Thus, you can just keep taking out edges from cycles in G until all that is left are cut-gees. Since you did not take out any cut-edges, the graph is still connected; since all that is left are cut-edges, there are no cycles. A connected graph with no cycles is a tree. Thus, G contains a spanning tree. Therefore, a graph G is connected if and only if it has a spanning tree!


Prove that a graph G is connected and only if it has a spanning tree?

Proving this is simple. First, you prove that G has a spanning tree, it is connected, which is pretty obvious - a spanning tree itself is already a connected graph on the vertex set V(G), thus G which contains it as a spanning sub graph is obviously also connected. Second, you prove that if G is connected, it has a spanning tree. If G is a tree itself, then it must "contain" a spanning tree. If G is connected and not a tree, then it must have at least one cycle. I don't know if you know this or not, but there is a theorem stating that an edge is a cut-edge if and only if it is on no cycle (a cut-edge is an edge such that if you take it out, the graph becomes disconnected). Thus, you can just keep taking out edges from cycles in G until all that is left are cut-gees. Since you did not take out any cut-edges, the graph is still connected; since all that is left are cut-edges, there are no cycles. A connected graph with no cycles is a tree. Thus, G contains a spanning tree. Therefore, a graph G is connected if and only if it has a spanning tree!


Is tree a bipartite graph?

Yes. A graph is bipartite if it contains no odd cycles. Since a tree contains no cycles at all, it is bipartite.


Define tree in data structure?

Tree is directed, cycle-less, connected graph.


What is spanning tree in data structure?

A spanning tree is a tree associated with a network. All the nodes of the graph appear on the tree once. A minimum spanning tree is a spanning tree organized so that the total edge weight between nodes is minimized.


Tree is also called as 64 because?

it was a seed in starting ,after few days it becomes plant then it becomes tree due to growing age it becomes big tree in age 64


Is a number line a graph?

Not by itself. It is only the framework. But as soon as you mark up one point on it it becomes a graph.