Matching and Covering

Description: This quiz covers the concepts of matching and covering in graph theory. Questions will assess your understanding of different types of matchings, covering theorems, and their applications.
Number of Questions: 15
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Tags: graph theory matching covering menger's theorem perfect matching maximum matching
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In a graph, a matching is a set of:

  1. Disjoint edges

  2. Disjoint vertices

  3. Disjoint paths

  4. Disjoint cycles


Correct Option: A
Explanation:

A matching in a graph is a set of edges such that no two edges share a common vertex.

Which of the following is a necessary condition for a graph to have a perfect matching?

  1. The graph must be bipartite

  2. The graph must be connected

  3. The graph must have an even number of vertices

  4. The graph must have a cycle


Correct Option: A
Explanation:

A necessary condition for a graph to have a perfect matching is that it must be bipartite.

Menger's Theorem states that the maximum number of edge-disjoint paths between two vertices in a graph is equal to:

  1. The minimum number of edges in a cut separating the two vertices

  2. The maximum number of edges in a cut separating the two vertices

  3. The minimum number of vertices in a cut separating the two vertices

  4. The maximum number of vertices in a cut separating the two vertices


Correct Option: A
Explanation:

Menger's Theorem states that the maximum number of edge-disjoint paths between two vertices in a graph is equal to the minimum number of edges in a cut separating the two vertices.

In a graph, a vertex cover is a set of vertices that:

  1. Covers all the edges of the graph

  2. Covers all the paths of the graph

  3. Covers all the cycles of the graph

  4. Covers all the connected components of the graph


Correct Option: A
Explanation:

A vertex cover in a graph is a set of vertices such that every edge of the graph is incident to at least one vertex in the set.

Which of the following is a necessary condition for a graph to have a vertex cover of size k?

  1. The graph must have at least k vertices

  2. The graph must have at most k edges

  3. The graph must have a cycle of length k

  4. The graph must have a path of length k


Correct Option: A
Explanation:

A necessary condition for a graph to have a vertex cover of size k is that the graph must have at least k vertices.

Which of the following is a sufficient condition for a graph to have a perfect matching?

  1. The graph must be bipartite and have an even number of vertices

  2. The graph must be connected and have an even number of vertices

  3. The graph must be regular and have an even number of vertices

  4. The graph must be complete and have an even number of vertices


Correct Option: A
Explanation:

A sufficient condition for a graph to have a perfect matching is that the graph must be bipartite and have an even number of vertices.

Which of the following is a sufficient condition for a graph to have a vertex cover of size k?

  1. The graph must have a cycle of length k

  2. The graph must have a path of length k

  3. The graph must have a clique of size k

  4. The graph must have an independent set of size k


Correct Option: C
Explanation:

A sufficient condition for a graph to have a vertex cover of size k is that the graph must have a clique of size k.

In a graph, an edge cover is a set of edges that:

  1. Covers all the vertices of the graph

  2. Covers all the paths of the graph

  3. Covers all the cycles of the graph

  4. Covers all the connected components of the graph


Correct Option: A
Explanation:

An edge cover in a graph is a set of edges such that every vertex of the graph is incident to at least one edge in the set.

Which of the following is a necessary condition for a graph to have an edge cover of size k?

  1. The graph must have at least k edges

  2. The graph must have at most k vertices

  3. The graph must have a cycle of length k

  4. The graph must have a path of length k


Correct Option: A
Explanation:

A necessary condition for a graph to have an edge cover of size k is that the graph must have at least k edges.

Which of the following is a sufficient condition for a graph to have an edge cover of size k?

  1. The graph must have a cycle of length k

  2. The graph must have a path of length k

  3. The graph must have a clique of size k

  4. The graph must have an independent set of size k


Correct Option: A
Explanation:

A sufficient condition for a graph to have an edge cover of size k is that the graph must have a cycle of length k.

In a graph, a maximum matching is a matching that:

  1. Has the maximum number of edges

  2. Has the maximum number of vertices

  3. Has the maximum weight

  4. Has the minimum weight


Correct Option: A
Explanation:

A maximum matching in a graph is a matching that has the maximum number of edges.

Which of the following is a necessary condition for a graph to have a maximum matching of size k?

  1. The graph must have at least k vertices

  2. The graph must have at most k edges

  3. The graph must have a cycle of length k

  4. The graph must have a path of length k


Correct Option: A
Explanation:

A necessary condition for a graph to have a maximum matching of size k is that the graph must have at least k vertices.

Which of the following is a sufficient condition for a graph to have a maximum matching of size k?

  1. The graph must have a cycle of length k

  2. The graph must have a path of length k

  3. The graph must have a clique of size k

  4. The graph must have an independent set of size k


Correct Option: A
Explanation:

A sufficient condition for a graph to have a maximum matching of size k is that the graph must have a cycle of length k.

In a graph, a minimum vertex cover is a vertex cover that:

  1. Has the minimum number of vertices

  2. Has the minimum number of edges

  3. Has the minimum weight

  4. Has the maximum weight


Correct Option: A
Explanation:

A minimum vertex cover in a graph is a vertex cover that has the minimum number of vertices.

Which of the following is a necessary condition for a graph to have a minimum vertex cover of size k?

  1. The graph must have at least k vertices

  2. The graph must have at most k edges

  3. The graph must have a cycle of length k

  4. The graph must have a path of length k


Correct Option: A
Explanation:

A necessary condition for a graph to have a minimum vertex cover of size k is that the graph must have at least k vertices.

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